## Monster Girl Encyclopedia World Guide I: Fallen Maidens | Monsterization Case Studies

### Monster Girl Encyclopedia World Guide I: Fallen Maidens | Monsterization Case Studies | Monsterization

Monsterization is the phenomenon where humans and other races change into monsters by having mamono mana inside their body. It's mostly human women that become victims of monsterization, although there are a few exceptions. Regardless of race, it is purported that monsterization can basically only occur in females. In the section after this, we'll be explaining how human women change into monsters, but the orientation and magnitude of the changes to the body and mind vary depending on each individual and what monster race they are changing into. We would like you to bear in mind that, as with ''monster ecology,'' the commentary presented from here on is just a general explanation of the average monsterization phenomenon, and transformation.

#### Monster Girl Encyclopedia World Guide I: Fallen Maidens | Monsterization Case Studies | Monsterization | Until Transforming Into a Monster

Monsterization occurs when mamono mana gets inside the body of a woman. The most typical way for this to happen is by infusion of mamono mana through sexual intercourse, as done by the succubus (encyclopedia I – p. 8), etc., but there are various other processes through which mamono mana could invade a woman's body and change her into a monster.

Women who have had mamono mana poured into them will have the essence within their body discharged as if driven out by the other energy. Otherwise, their essence will be converted into mamono mana, as if it were being swallowed by the mamono mana.

Whatever the case, monsterization is completed at the same time as they completely lose their mana, and a woman will end up being reborn as a monster. When mamono mana gets inside a woman's body, it causes her body to flush, and dimly dulls her thoughts. This ensures that she can't resist the temptation and pleasure from a monster, and makes it so that she will receive an even larger amount of mamono mana. The more the body becomes brimming full of mamono mana, in proportion, the closer her mind and body approach that of a monster.

Mamono mana changes the body into a monster-like, sensitive one that can greedily receive pleasure. Even the kind of pleasure that monsters enjoy regularly is far too strong and intense for humans, and it would shake them. Pleasure like an electrical shock would paralyze them to the degree that it would even immobilize their mind and body, staining them completely in the color of pleasure. In the same way, the more the body becomes filled with mamono mana, the more changes appear. If essence flows out of the body as mamono mana is poured in, so too does everything that gets in the way of receiving pleasure such as inhibitions, reason, self-restraint, and repugnance for monsters and pleasure, etc. It probably feels as if the heart has become lighter. Once the heart loses everything excessive, before long, it is filled with ''a good feeling'' that makes a monster's desire to seek and enjoy pleasure sprout. If essence starts to change into mamono mana, at the same time, human values and thoughts are painted over by devilish pleasure, and one can understand that she's changing along with a sense of pleasure and depravity. For humans, the sensation of mamono mana swelling within their body and essence changing into mamono mana is accompanied by an extremely sweet feeling.

Just before completely changing into a monster, one can sense that she's being enveloped by thick mamono mana, and having her body filled by it is felt like a wonderful thing. And then, due to monsterization, the body will begin to transform and what they are likely to feel when parts that they lacked as a human start growing from their body is intense pleasure, and a strong feeling of liberation. Upon experiencing this sweet sensation, even their tears that had at first come from fear, sadness, and despair change into tears of joy for having become a monster by the time they transform.

Even in the case when one escapes before completely becoming a monster, the mamono mana that entered the body usually never disappears. If it's an extremely miniscule amount, then it will disappear after a while, but if the amount is larger, then it's often too late, even for those who haven't yet turned into a monster. Mamono mana remaining in the body continues to alter the body and mind from within. Once the body has tasted the sweet sensation of mamono mana flowing inside, one is unable to forget the decadent pleasure of a monster, and her body will burn hotly. Her mind will be troubled by obscene thoughts and images, and the erotic dreams she'll be having every night, and desire will grow. Eventually, she'll become unable to bear it, and she'll descend to a monster on her own seeking the pleasure of a monster, and to transform into a monster.

Furthermore, essence is the vital energy possessed by humans. In other words, it could also be called ''human magical energy.'' Of course, the kind of women referred to as heroes and great sorceresses also possess lots of this mana. When they have their body violated by mamono mana and are monsterized, this vast amount of essence is converted into mamono mana, so the more powerful someone was as a human, the more powerful and lascivious the individual will become like a monster as well.

When human women change into monsters, big changes appear in both their body and mind. Basically, their values and thoughts from when they were human disappear, and change into the monster thoughts and values which are explained from p.37, but they're different from those of monsters that were born a monster. There are also sensations they can feel and values they possess especially because they were originally human. Let's focus on that point, and explain what sorts of changes happen to them.

#### Monster Girl Encyclopedia World Guide I: Fallen Maidens | Monsterization Case Studies | Monsterization | Physical Changes

The appearance of women who has become a monster changes hugely. Their appearance is altered based on their appearance from when they were human. Their face becomes devilishly beautiful or cute to the degree that eyes of men are always drawn to them. The body changes into a charming body that inspires carnal desire in men. While their appeal is different depending on the race and the individual, with everything from mature adult women, slender, beautiful girls, and little girls with decadently soft skin, every monster has an appearance that looks beautiful or cute to a typical human man. It's the same for those who change from human to monster. No matter who the woman is, once they change into a monster they will change into a beautiful and lovely form for tempting men.

Furthermore, the change is always based on their face from when they were human, and in most cases, the changes occur along the lines of accentuating the attractiveness of the original, so, for example, even if there are huge changes, it's not like they change into a completely different person. It always ends up so that they bear a strong resemblance to the original woman.

As for additional huge changes, the color of the skin will change to match the characteristic of the monster's race, and the organs and parts characteristic of the race will appear. Beast ears and tails, demon horns and wings, etc. will grow, and depending on the race, the lower body may also change into a grotesque form.

Compared to humans, monsters have extremely tough bodies and high physical abilities. Also, since monsters mostly don't catch the kind of diseases that humans catch, even if their body was weak as a human, or they were afflicted with an illness, they mostly become healthy due to monsterization. To those who had lived in a human body up to that point, with a monster's body, it is likely to feel like they're in a good condition and capable of doing anything. Compared to when they used to be human, their body feels lighter as if freed from bindings, whereas before, on the contrary, it used to feel heavy.

Also, to those who were born as monsters, it's just normal, so it's hard to understand the feeling, but according to those who used to be human, compared to when it was a human body, a monster's body, which always actively seeks men, feels as if it's engulfed in a sensation of warmth and exaltation.

After a while, the body feels hot, and blood rushes to their head, and then they'll seek to have sex for the first time after becoming a monster, and they'll attack a human man. Also, the way to use their body is engraved in their instinct, so they can probably move freely and use it right after becoming a monster. Naturally, as soon as they change into a monster, the methods of how to attack men, milk essence, and use their body are imprinted in their instinct, so right after changing into a monster they can actively attack men and enjoy essence and pleasure.

A monster's lewd body is extremely sensitive compared to that of a human woman so that they can actively receive pleasure. If one has sex with that body, the amount of pleasure received is many times greater than the pleasure that can be obtained by having sex with a human body. In the case of human women, the pleasure is so powerful that their mind cannot process it and they'd pass out, but in the case of monsters, their level of tolerance for pleasure is in another league, so they can enjoy that sort of pleasure and indulge in it. The devilish pleasure experienced by those who have sex with a man for the first time after changing from a human to a monster makes them reconfirm how wonderful it is that they've changed into a monster and they are a monster. It's enough to make them think _I can't go back to being human anymore,_ or _I don't want to go back to being human._ Once this happens, they become a prisoner of the lewd body they obtained by becoming a monster, and the pleasure of using it, and in monster-like fashion, they just keep becoming even more lascivious than those who were monsters, to begin with.

#### Monster Girl Encyclopedia World Guide I: Fallen Maidens | Monsterization Case Studies | Monsterization | Mental Changes

As with the body, the changes caused by becoming a monster have a huge impact on a woman's mind. Those former humans who became monsters don't feel fear or despair from having changed into a monster or changed into a grotesque form. Even if they experience despair until just before or right after the transformation, it will disappear in an instant. If one transforms into a monster, she'll literally be engulfed in a feeling of liberation and ecstatic joy as if she has been reborn. The joy of having obtained a devilish body that can bewilder men and make them drown in it, magnify the pleasure of sex by many times, and enjoy and indulge in it. And then, arousal and the anticipation of using and enjoying that body plenty from then on washes away despair and such.

As for women who become monsters, the disgust and resistance towards sex that they had when they were human disappears, and a monster-like thirst for pleasure and essence wells up. Moreover, so that they can indulge in it, they are released from the inhibition and restraints, etc. that were troublesome when they were human. The heart will feel lighter, almost like being in a dream, enveloped by a fluffy, happy feeling. And then, as if to trade places, the affection for human men necessary for satisfying the thirst for essence and pleasure will overflow endlessly. By becoming a monster, they become able to sense the odor of men's mana, and the obscene desire that men direct towards them. And then, they end up recognizing them as wonderful things.

Due to this, they realize that men are delicious-looking, cute, and very wonderful things that will satisfy their own desires. If they become like this, then afterward, they'll already be ruled by a monster-like desire to assault and have sex with men. No matter how prudish they were and how much they hated men to begin with, they'll end up strongly wanting and loving men. Additionally, upon changing into a monster, if there's a man they want, then they'll just give in to desire and seek him. Upon realizing that they themselves are equipped with the body, beauty, and ability to imprison a man and make him their own, their heart will be overflowing with self-confidence and hope.

The desire for men that's taken root in them, and this self-confidence, will make them arrive at such thoughts as _If a man hates and fears me, then I'll just thoroughly ravish him and make him my very own prisoner,_ _If my feelings are unrequited, then I'll just thoroughly gratify him and make it so that he can no longer live without me,_ and will cause them to attack men without hesitation.

And then, once they know the pleasure of sex with men and the taste of mana, to someone who lived as a human until that point, it's something that feels like the most wonderful happiness they've ever felt in their entire life. It's said to be so much so that they'll even come to regret their human past, thinking something like _Why didn't I realize all this time that there was something that felt this good, something that was this delicious, and that becoming a monster was something so wonderful?_ After that, as if trying to make up for the period when they were human and unaware of such pleasure, they'll become engrossed and keep having sex, and they'll end up continuing to indulge in pleasure as if to verify the happiness of becoming a monster and getting what they want.

Also, as with the body, their personality and memories from when they were human will end up largely remaining intact. As with the body, the changes brought about by monsterization will mostly accentuate the appeal of their original personality. At a glance, it might seem as if their personality hasn't changed at all from before, but monsters always acquire a monster-like, lustful personality without exception, and their thoughts are disposed to end up being hedonistic.

For example, a shy village girl who was afraid of men will retain her looks that spur a man's desire to protect, and modest personality, but she'll start to actively tempt a man, deliciously suck and lick a penis in her mouth, straddle a man's lower body, and furiously ravish him. A diligent female knight that never missed a day of practice and gave off an air of nobility will retain her diligence, and she'll mount a man's body every single day and perform sex. Her normally noble attitude and appearance would be retained, but she would become pleased to receive a man's desire to tarnish her noble figure with his body.

Among them, there are some changes to personality that match the race, and certain flaws and feelings of inferiority that a person used to have will change to become erased, etc. so there are also those whose personalities change greatly, but on the other hand, there are also those who used to pretend to be something they were not when they were human, so when their true personality comes to the surface, it looks like their personality changed. However, even in such cases, the original personality is never lost entirely, and each individual's essence doesn't change. There's always a part that remains which makes one feel a ''resemblance'' to the original individual from before they became a monster.

Moreover, personality changes such as these appear in a monster-like direction to ensure that they feel fondness and desire towards men, and depravity, etc. Additionally, by changing into a monster, a sadist who enjoys inflicting wounds on others and making them suffer will change into a sadist who enjoys forcibly raping others and pleasuring them willingly or unwillingly. In a monster-like fashion, they'll change to have a sense of disgust towards killing humans. Due to these changes, there are probably also those whose personalities appear to improve by becoming a monster.

Concerning a person's memories from when they were human, they're basically carried over unchanged even after becoming a monster. Sometimes memories that the person herself desires to forget become fainter, but omitting some exceptions, memories are almost never modified.

A person's feelings and affection towards people, of course, remain intact. On the contrary, by becoming a monster, the very incarnation of love and desire, the love swells up enormously inside them. Feelings towards a man that one possessed as a human will end up blossoming by becoming a monster, for instance, if there was a man that they had a strong love for such as a boyfriend, husband, or lover, etc. then the lascivious desire directed towards him swells up. A monster's instinct will recognize him as her husband, and after becoming a monster, the body and mind will start to change to belong exclusively to their husband even before they have sex.

For that reason, a woman who had just become a monster that we would normally expect to have such a powerful urge for sex that she would just push over anyone and have sex with them without caring would actually become able to sensitively detect her husband's mana, and pursue the hints of his presence, and she would head straight to him without even glancing at other men.

#### Monster Girl Encyclopedia World Guide I: Fallen Maidens | Monsterization Case Studies | Monsterization | Invitation to Monsterhood

Monsters basically have an instinct to attack human men, but some among them have an instinct to attack women to increase their allies, and there are some who just try to attack women on a whim. Before we get into the reasons, first we'll explain how monsters think of human women.

Presently, the Mamono Lord has the ambition to unify them into one race, with humans as males, and monsters as females. For that reason, as far as monsters are concerned, human women are beings that are destined to subsequently become the same race as them. As with human men, they approach them with affection and don't like hurting or killing them for no reason.

Also, when they see human women unable to fulfill their desires and bearing them patiently when their desires are inhibited by human rationality or human society, etc., monsters feel sorry for them. When a monster sees the way many adherents of the Order have disgust for sex and pleasure and try to distance themselves from it, it makes her think it's a waste: _How could she not know something that feels so good?_

When the monsters that live happily amid pleasure see a woman like that, they unconsciously end up feeling like teaching the woman about the joy of sex. Monsters that have converted human females into their own race in this way have fun and enjoy watching the uninhibited appearances of those they personally changed into monsters such as the sight of a woman who used to be troubled by being unable to fulfill her desires pushing down her loved one and imprisoning him using her own power, or the sight of a little girl that had never known pleasure until then, drowning in pleasure, falling and becoming lascivious, etc.

In this way, surprisingly, the reason monsters change human females into monsters is mostly to meddle, or just for amusement.

Also, women who changed from human to monster have a more remarkable tendency to do so. They're extremely aggressive about changing human women into monsters. They know the joy of changing from a human to a monster, something that those born as monsters have never tasted. Additionally, since they have memories and feelings from when they used to be human, they compare their current life to their old one, and they think of life as a monster, indulging in pleasure and mana, and spending one's time making love with a man, is extremely wonderful. To them, the wonderful world that they now live in that's full of desire and the odor of men's essence inspires them as a female, but compared to it, the world when they used to be human will likely be regarded as extremely hollow. For that reason, they want to share pleasure and happiness with human women, and they think that women should abandon their humanity as soon as possible and join them on this side. In order to free them from the shackles of humanity, and guide them to the paradise known as monster hood, they aggressively attempt to change human females into monsters.

Also, in addition to such thoughts, there are those among the monsters who regard human women as incomplete beings, who don't even adhere to the monster's principles of faithfulness and are unable to imprison and rule men through pleasure. There are even those who believe all women should become monsters, and they aggressively try to convert human women into monsters whenever they find them. Monsters with these kinds of beliefs are called ''radicals.''

### Monster Girl Encyclopedia World Guide I: Fallen Maidens | Monsterization Case Studies | Incubus

An incubus is mainly a human man that kept receiving mamono mana and containing it within his body, resulting in a transformation into a being that's convenient for monsters, possessing superhuman stamina and lust. Under the current concept, monsters are all female beings that only possess mamono mana, so an incubus, which is male, and possesses both energy and mamono mana at the same time, is not a monster. Ultimately, they're just humans altered by mamono mana. However, the Order regards them as being the same as monsters, and they're targeted for expulsion and suppression.

#### Monster Girl Encyclopedia World Guide I: Fallen Maidens | Monsterization Case Studies | Incubus | Until Changing Into An Incubus

Compared to monsterization, in which changes suddenly appear, changes caused by incubization are extremely gradual. Unlike a woman's monsterization, where they totally change into a monster both mentally and physically after having sex one time, the changes that occur when a man transforms into an incubus and afterward, appear bit by bit each time he has sex with a monster.

Human men transform into an incubus by having sex with monsters, and having mamono mana poured inside of them. Unlike women, who recover energy by absorbing it from the air, men continue to produce energy within their own bodies, so compared to women, it's more difficult for mamono mana to take hold, and they do not change into an incubus just from having sex once.

In the case of the succubus family of monsters, they possess ''succubus' energy'' which has a higher retention rate, and causes men to release more energy in a single session of sex by infusing them with it, so compared to other monsters, incubization is extremely fast, and in the case of a powerful succubus, it's even possible to change a man into an incubus by having sex once.

Also, even if it's a monster of another race, after spending a long time as their husband, and living beside them, by continuing to have sex, mamono mana gradually takes hold in the body after each time, and eventually, a man will transform into an incubus.

Additionally, even monsters not of the succubus family can accelerate the incubization process by continuing to ravish a man with multiple monsters, and aside from that, there is ''succubus' secret elixir,'' a medicine made from succubus' energy, and there are special rituals and spells that can be used to quickly change a man into an incubus.

When transformation into an incubus occurs, it's not like one can clearly tell that he's transformed, as was the case when a woman is monsterized. In the case of monsterization, a woman is able to grasp that she's become a monster because of the changes in her body, and a feeling of ecstasy like she's been reborn, but in the case of incubization, before one knows it, he's already changed into an incubus.

In the course of getting continuously violated by monsters over and over, a man who at first would tire soon, exhaust his mana, and pass out, will steadily increase the amount of time he can have sex, and the number of times he can release energy increases. In the beginning, the pleasure is so violent that one can't even think straight, but one gradually becomes able to enjoy the pleasure. Gradually one will change so that he can't help but consider having sex with the monster in front of him, and gradually, he'll come to desire to be ravished by the monster before his eyes. In this way, bit by bit, one will change into an incubus without being aware of it.

What makes an incubus an incubus, and a man is an energy within his body and the existence of a energy production faculty. Very rarely among the incubi, there exist those who unconsciously destroy their own energy production faculty. In that case, energy will not be produced, and the body of an incubus who loses energy and is completely ruled by mamono mana will completely change into a monster. This monster is called an Alp.

#### Monster Girl Encyclopedia World Guide I: Fallen Maidens | Monsterization Case Studies | Incubus | Mental and Physical Changes Caused by Incubization

As for changes caused by incubization, the changes that appear basically make it convenient for the monster that one is coupled with.

First, it is purported that the looks almost don't change at all compared to when one was human. Monsters don't care very much about the attractiveness of a man's face, so in most cases, there are no changes whatsoever. The body changes to become more healthy and durable so that it's convenient for sex, but it's rare for the appearance to change greatly other than that.

A rare exception occurs and the appearance greatly changes in the case of those who are too feeble or fat, and their form will be vastly improved so that it's convenient to have sex with monsters. Also, in the case of those who are so old that it's a hindrance to sex, they will also be rejuvenated.

After one has changed into an incubus, the mind also changes so that one's values become nearer to those of the monsters, but compared to monsterization, even if only a little bit, human-like values from the period when one was a human will remain. However, the values and thoughts of an incubus, a being that became a monster's prisoner so much so that it altered the nature of his mind and body, will change to become eager to have sex with monsters. One's lust will swell up like that of the monsters, and disgust towards monsters and sex, etc. will have long since disappeared, and one will change so that he aggressively desires sex with monsters.

Also, after being completely charmed by a monster, one's aesthetic sense will have changed so that he feels that the grotesque parts and organs of monsters are beautiful. Other than that, one's sense of time and values concerning work and recreation will also change so that it becomes more convenient to live with monsters.

The biggest changes of all occur in the functions that are also most important to monsters that get used during sex. It depends on the race and preferences of the monster that one is coupled with, but most men who become an incubus will have their penis grow larger by leaps and bounds, and they'll be able to please monsters even more. The amount of semen and energy released from there will be incomparable to when they were human, and they'll have boundless stamina so that they're able to release it again and again without getting exhausted.

The quality of the energy is also remarkably different. It becomes so much thicker, stickier, and sweeter, that it's incomparable to when they were human, and one lick will make a monster melt. Also, human men sometimes lose the mood after expelling mana, but it doesn't occur in an incubus, and their lust for monsters just flares up.

In addition to the normal food that they ate when they were human, it's also possible for an incubus to feed on mamono mana by having sex with monsters. For that reason, an incubus never gets exhausted when having sex with a monster. Instead, their entire body will brim full of lust and energy due to mamono mana. When the body of an incubus obtains mamono mana by having sex with a monster, it will immediately produce mana. When this energy is released to a monster, the monster will produce mamono mana from it and pour it into the body of the incubus.

Astonishingly, with this cycle, not only does the total amount of magical energy not decrease, instead, it continues to increase, so it's possible for a monster and an incubus to keep having sex almost forever, and as long as there's one incubus and one monster, it's possible for them to live by just having sex. As far as the divinities and the Order are concerned, this nearly perpetual cycle is something that is in violation of divine providence that will greatly throw off the laws of the universe and is extremely viewed as a problem.

Also, it's said that the lifespan of men who become an incubus becomes dramatically longer. Since they can keep living by having sex with each other, their lifespan is roughly the same as the monster that they're coupled with. Just like monsters, their appearance stops aging at a certain stage. It could be as a boy, as a young man, or as a mature man. Since an incubus is a being that's convenient for a monster, they change depending on the tastes of the monster that they're paired with. In this way, an incubus is none other than an ideal male to a female monster.

The power of an incubus grows stronger the more mamono mana they accumulate. In the case of those that periodically have sex with multiple monsters, it piles up, so in the case of a single incubus that makes a harem of multiple monsters and keeps having sex with them, it ends up causing the birth of an extremely powerful incubus. Regardless of how many monsters are in the harem, an incubus has limitless stamina and lust, and can have sex with all of them. Even if an incubus keeps having sex with them day and night alternatively for a period of several days, he'll never get tired, lose his erection, or feel pain or boredom. On the contrary, he'll end up being unable to get satisfied unless he has sex with all of the monsters in the harem, and it'll even get to the point where it's as if spending several days having sex with all the monsters in the harem is like having sex one time to him.

Additionally, those who become an incubus can also adapt to the environment to match the monster that they're coupled with. For example, an incubus coupled with a monster that lives in a desert, or near a volcanic crater, will gain resistance to heat, and an incubus that is coupled with a monster from a snowy country will gain resistance to cold. They gain such strong resistance that they can even actively have sex with monsters in such environments. To provide a remarkable example, due to a ritual performed by a ''sea bishop'' there are incubi that became able to live underwater. This ritual is performed to quickly change someone into an incubus, so as a result of having been changed into an incubus with the mamono mana of the monsters of the sea, they've adapted to live underwater.

Since an incubus retains the mamono mana of the monster he's coupled with inside his body, a human woman who has sex with an incubus will end up transforming into that race. However, the lust of an incubus who's kept having sex with monsters will not be satisfied by having sex with anyone other than a monster.

Also, an incubus' superhuman lust is only directed towards the monster he's coupled with no matter what, and they don't have an instinct to attack the opposite sex as monsters do. For that reason, incubi do not attack and forcibly rape human women, and such an incident has never been confirmed.

### Monster Girl Encyclopedia World Guide I: Fallen Maidens | Monsterization Case Studies | CASE 01: Sexual Intercourse

>Ahh... it's so nice to be a demon... 😈 Being one with the one you want, becoming beautiful, feeling good, having a superb body... Ahh, it's like a dream! 🤩
>
>—*Formerly a Human Village Girl / A Succubus*

Many of the monsters that change human women into monsters do it by having sex with them and pouring mamono mana inside of them, changing them into a monster. Among the methods of monsterization used by the monsters, this is the one most often used, and it is regarded as the most efficient method as well. As for monsterization via sex, since the bodies are pressed closely together, it's easy for mamono mana to flow inside. Also, if one melts a human woman's mind by giving her pleasure, it will greatly lower her resistance to mamono mana, making it possible to smoothly convert her into a monster.

When performing this sexual intercourse, among the monsters there are also those who will attempt to thoroughly instill the woman's body with pleasure, developing her erogenous zones and making her lewd skill capacity blossom, so that she will become an even more lascivious monster. Women who learn the sweet taste of pleasure during this occasion will be more aroused and have even greater anticipation for sex with a man which will come later, along with even greater pleasure.

After getting a thorough sexual education in this manner, ex-human monsters are mostly very grateful and have respect for the monster that converted them into a monster. It is said that there are those who adore the monster who granted them sweet ecstasy and a pleasurable body, calling her ''onee-sama,'' and in the event that they obtain a human man, they will try to show onee-sama just how lewdly they've grown.

The ''succubus'' is the most iconic monster that uses this method. The hedonistic succubi have a strong inclination for enjoying the sexual act of converting these human women into monsters, and seeing how things progress for them afterward. Since most of them try to enjoy sex to the maximal extent, on the occasion of converting a human woman into a monster, naturally, they can really get into the sex, and the amount of pleasure and mana given to a woman will increase in proportion to how much they're into it. Also, most of them prefer to do sexual education while having sex, and when converting a woman into a member of their own race. Creating an even more lustful succubus becoming of a succubus is one of their main pleasures. The body becomes more indecently sensitive, and the mind becomes lascivious to the point that it's full of pleasure. They create such succubi, and enjoy watching their figure lewdly melt as they have sex with men, whether day or night. The more pure, clean, and ignorant of pleasure their prey is, the more fired up a succubus gets, and the more she enjoys training her prey and converting such a girl into a lewd succubus.

!["No, aah....! Don't....!" "Heehee! 😘 It's okay. It'll get good soon... 🥰" The spoils of war will soon know pleasure, even if they were prim, even if they were fastidious, these women will become a lewd succubus. Causing this flare-up in their spoils gives succubi a great amount of pleasure.](https://mgewiki.moe/images/c/cd/FM_Monst_1.png)

!["I can't believe I can do such a wonderful thing.... 😳 I can't believe I'm able to do such a wonderful thing for you..... 🥵" She wasn't confident as a woman, but once she became a beautiful and lewd succubus, she has the confidence to enjoy the pleasure she can indulge in with her favorite man; her dreams are coming true.](https://mgewiki.moe/images/a/ad/Fm_Monst_2.png)

### Monster Girl Encyclopedia World Guide I: Fallen Maidens | Monsterization Case Studies | CASE 02: Essence Corrosion

>Haa... Haa... my body's getting hot... 🥵 hey... can you help me...? 😳
>
>—*Female adventurer lost in the Mamono Realm/Human*

Mamono mana (or mana), floating free in the atmosphere, will slowly flow into a human woman's body, accumulate, and eventually, once enough has built up, change her into a monster. Thanks to the phenomenon of the Mamono Realm constantly releasing, and being steeped in monstrous mamono mana, any women who visit a Mamono Realm for a period of time will become a Succubus.

Unlike being assaulted by a monster, exposure to energy is a slow, gradual process. A woman who is exposed to energy will find herself becoming more and more excited as the energy trickles into her, eventually, her thoughts fading as she enters an oestrus. Her body heating up little by little and becoming feverish, she'll also take a special interest in any companions with her as her body becomes more sensitive to pleasure.

Once the woman has entered oestrus, her body feverish with desire, it is already too late for her, in this state, she is already on the verge of becoming a monster. Spotting a man, she will attack him, and when he releases his essence, this will provide the final burst needed to completely change her into a monster.

During this phase, the affected women, their body feverish and minds foggy, find it impossible to resist these feelings and it is inevitable they will change into a monster when they come across a man. Having just transformed, their bodies will seethe with fever and lust, thanks to this they will continue to force themselves on the man that just helped them transform.

For those traveling in the Mamono Realm, particularly heroes sent to slay the Mamono Lord, this constant corruption caused by the monstrous energy flooding the atmosphere is a big problem. Even though you can avoid or fight off monsters, there is nothing that can be done to prevent this corruption from occurring.

So far, only two female heroes, a two member party, managed to reach the Mamono Lord herself, they were, however, already on the verge of becoming succubi and were given their last push by the Mamono Lord's own hand. So far no hero or heroine has managed for the face-off against the Mamono Lord without becoming a Succubus or Incubus and joining her army's ranks.

In addition, the type of Mamono Essence that a human woman is exposed to can change the species of monster she'll become, different areas producing different types of mana. For example, a woman who drowns at sea is invaded by Poseidon's energy changing the woman into a Nereid.

### Monster Girl Encyclopedia World Guide I: Fallen Maidens | Monsterization Case Studies | CASE 03: External Wounds

>How is it? The wound gouged out by my fangs? How is it? The wound torn by my claws? They're hotly throbbing, right? Soon you'll be at ease... because soon, you too will become a beast.
>
>—*The last words a female soldier of the Order heard just before changing into a werewolf*

Monsterization can occur due to a variety of reasons, and there's also the danger of a human woman changing into a monster as a result of a wound sustained from a monster attack. External wounds caused by claws and fangs infused with a werewolf's energy cause energy to pour out of the body instead of blood. And after energy pours out, their mamono mana will be poured in. In a woman's case, she will be changed into a werewolf the same as them. No pain is felt from such wounds. Instead of hurting, the wound heats up and continually throbs. The hot throbbing of the wound gradually spreads throughout the body. The heat of the wound causes the body to flush, and the throbbing of the wound causes the body to throb, remaking a woman's body into that of a monster. Basically, the wound completely heals at the same time a woman changes into a monster, but by that time, their monster body will be seeking a man and their monster womb will begin to throb with even more heat, seeking sperm.

Mamono Realm weapons made using ''Mamono Realm silver,'' a special metal produced exclusively in the Mamono Realm, and special weapons made from hardened mamono mana have the same effects as the claws and fangs of werewolves as described above. They can inflict wounds not on the body of a living thing, but on a living thing's ''mana.'' Due to these sorts of weapons, once a large external wound is sustained, energy pours out, and the mamono mana contained in the weapon flows in, causing women to change into monsters such as ''succubi,'' etc. These weapons were produced especially because of the monsters' disdain for injuring and killing humans. They are widely distributed and used by monsters such as those in the Mamono Lord's army. They are actively being used even in battles with the Order's troops. They're changing the soldiers of the Order into monsters like themselves instead of corpses. Battles between humans and monsters end with extremely few dead and injured for the human side thanks in large part to the existence of these weapons.

Furthermore, the effectiveness of Mamono Realm weapons varies greatly depending on the quality of the weapon used as a catalyst, the quality of the mamono mana-infused, and the skill of the one wielding it. In the case of a weapon where all those qualities are low, even if a woman is cut and some wounds are inflicted, it won't result in monsterization. However, on the contrary, if all the standards are high, such as in the case of a ''Dullahan'' master fencer wielding a sword made by a ''Cyclops'' artisan with the concentrated energy of a lilim, then even a scratch can result in monsterization. A wielder of such a weapon leaves a mountain of monsters in heat in her wake rather than a mountain of corpses.

### Monster Girl Encyclopedia World Guide I: Fallen Maidens | Monsterization Case Studies | CASE 04: Parasitism

>Aha~ 😍 An egg went inside... 😲 My baby, she is bouncing with joy inside your womb... 🤤
>Heehee, hurry up and be born so we can get off together... 🥰
>
>—*A maid working at Lescatie Castle / Roper*

Even among the numerous varieties of monsterization, this ''parasitism'' is something extremely peculiar. ''Matango'' come from human women parasitically infected by mushrooms. ''Roper'' come from human women implanted with eggs and parasitically infected. Other than those, it is said that there are also slimes, etc. that are parasitic in women. Unlike other monsters which change women into monsters by infusing them with mamono mana, they implant things such as eggs and spores, etc. inside women, and make them grow inside women's bodies. By doing this, the women's bodies are remade from the inside, and changed into monsters.

The sensation of having the body physically remade from within is far greater than that which is caused by mamono mana. Having their whole body teased all over, kneaded around, and changed into something else is accompanied by extreme pleasure. Reason gets thrown out the window and their minds will be stained one color with pleasure. In the case of monsterization due to parasitism like this, even after changing into a monster, their human values and thoughts continue to linger for some time.

The parasite that infects her makes the host's body become unbearably hot and gives her extreme pleasure. By robbing her thoughts and implanting its own thoughts, it rules its host by seizing control of the woman's thoughts. The parasite's objective is a source of nutrition, and the obtainment of a human male partner for the production of seeds. The parasite can read which man she yearns for from the host's memories and feelings, and it will target that man, or target any man indiscriminately if there is no such person. The parasite will lead the host to a man by manipulating her thoughts and actions and will try to obtain the man using the host's body.

Eventually, the parasite will make the host have sex with a man, and absorb essence. Upon obtaining essence, the parasite begins rapid growth, binding itself with the host in an attempt to become one. After perfectly binding and fusing with the host in this way, the parasite will stop controlling the host, and will return all the thoughts that it had seized back to the host. However, after fusing with the parasite, the host will no longer have human-like thoughts or values. Her body and heart will have changed into those which belong to a lewd monster. The host's self-perception will also change. Until that point, she would have thought of herself as _a human parasitically infected with a monster,_ but due to fusion with the parasite, she would start to think, _I, myself, am a monster._

Since the parasite's instinct and memories are also completely fused, even though she'll have the memories of being manipulated as a host, she'll also have the memories of doing the manipulation as the parasite at the same time. Ecstatic two-fold joy springs forth, since she was reborn as a host, and she obtained her own body as a parasite. Their thoughts and behavior objectives become based on the parasite's instinct. That objective is mainly to keep having sex with their beloved and obtaining essence which is a source of nutrition. And then, they'll implant their own egg or spore, etc. inside a human woman and change her into their own kind.

This is the troublesome thing about them. Unlike other races that change human women into monsters for amusement or to be meddlesome, attacking human women and changing them into monsters is their main objective. Since it's the equivalent of becoming pregnant for other monsters, they strongly desire it, and since they do it aggressively the following sex with a man, if one of them appears, it will cause a widespread outbreak in no time at all. Villages, towns, and in the worst-case scenario, entire nations of matango and roper will be formed.

### Monster Girl Encyclopedia World Guide I: Fallen Maidens | Monsterization Case Studies | CASE 05: Melting

![An assassin with a hard, icy heart who had undergone training to kill emotion. If enveloped by a dark slime, even a woman like that will...](https://mgewiki.moe/images/d/d7/Transformation_Dark_Slime_1.png)

![After her body and heart have softly melted due to pleasure, she is reborn as a dark slime.](https://mgewiki.moe/images/6/6c/Transformation_Dark_Slime_2.png)

>Hey~ Hey~! 😘 Get sticky with me! 😜 There... put it inside my sticky pussy... 🥵
>I want you to shoot lots and lots of sticky semen! 😜
>
>—*Former human, assassin of the religious kingdom of Lescatie / Dark Slime*

It is unique even among the multitude of monsterization phenomena. As of the present, only ''Dark Slime'' uses this method. They envelop human women with their own half-liquid body, and in doing so, tease the woman's entire body, diving into and violating every single orifice. The messy body of the slime continually gives them sticky pleasure throughout their entire body that we can say is truly out of this world, melting away the woman's thoughts. As for women violated by dark slimes, everything melts into the dark slime, including their body, thoughts, knowledge, and memories. All of it mixes with the pleasure given to them by the dark slime, and their mind gets muddled.

After the woman's consciousness has been completely melted away by pleasure, before long, even her body melts away inside the dark slime and disappears. After the human body melts away and disappears, a ''slime core'' the same as one of those possessed by the slimes remains. After that, the woman's body is reformed from half-liquid goo based on her form from when she was human. In this way, after one's heart and body have completely melted away, a new ''dark slime'' is born.

Unlike other slimes, dark slimes are a race that possesses high intelligence and thinking abilities. For that reason, their knowledge and intelligence from when they were human remain intact, but since the inside of their head has been melted by pleasure, they think of everything based on sex and pleasure, and they use everything for that purpose. If they were originally a powerful sorceress, all of their spells will be used to heighten their enjoyment of sex with men. If they were originally military strategists gifted with great intelligence, they can come up with an elaborate strategy to imprison whatever man they have their mind set on.

### Monster Girl Encyclopedia World Guide I: Fallen Maidens | Monsterization Case Studies | CASE 06: Undead

> Uh... ah ah... I'm so cold... big brother... hey... fill my empty insides with it... 🥶 fill my insides full of your white stuff... 🥵
>
>—*Former human, younger sister who died during her first year as a soldier of the Order / zombie*

Mamono mana sometimes even dwells in the corpses of human women, resurrecting them as monsters. Monsters born in this way are called ''undead,'' there are many races, including ''zombie'' and ''ghost.'' Corpses in lands such as the mamono realm that are full of mamono mana will most certainly resurrect as the undead, but aside from that, there are also many who are intentionally infused with mamono mana and resurrected directly by monsters. Also, since it's in the nature of mamono mana to bind with powerful human emotions, it easily gathers in the corpses of those women who died with strong regrets, and those who left behind a man they deeply loved, so even in lands where there is little mamono mana, undead outbreaks are not uncommon.

No matter how horrific their wounds were at the time of death, the bodies of the undead are mended enough to be attractive to men. Rotting also stops, and they don't reek. The undead basically keeps their memories from when they were human intact, but many of them have diminished intelligence and capacity for thought due to a lack of essence. They'll try to assault human men and have their way with them due to an attachment to life and an attachment to sex. All of the undead are fueled by the essence of human men, and through it, they maintain their bodies.

At first, they are dim-witted, and hardly seem to be alive, but the more they have sex with a human man, the more they regain their beauty and wits from when they were alive. Not only that, as far as beauty is concerned, since they've become monsters, by continuously having sex, they grow even more alluringly attractive than they ever were as humans.

It is hypothesized that the monsters seek humans because of 3 desires, ''appetite'' ''lust'' and ''love.'' In addition, the undead have a fourth strong desire. It is an ''attachment to life.'' They sense life when they cling to a beloved man and feel the warmth of his body when they join with him, have sex with him, and are pierced by his cock, and when essence is poured into their body. They are always continuously seeking to have sex with a man, the only thing that makes them feel alive. Most of them would rather not separate from a conjoined state with their beloved if at all possible.

Furthermore, as mentioned previously, by continuously gaining essence, the bodies of the undead are mended to the state they were in before death. An undead that is continuously pumped full of tons of essence every day can even completely mend her own womb, if she so desires, and then it's even possible for her to become pregnant with the children of her beloved. For an undead, the sense of life she gets at the moment of conception is the greatest happiness she can ever know as an organism, and as a monster female. During pregnancy, at the moment of the child's birth, and even afterward, this joy will always remain with her. The children born on such occasions are not human children. If it's a zombie, then the child will be the same kind of zombie. For this reason, it is said that the undead aren't ''human corpses reanimated via mamono mana,'' but ''organisms called undead that are reborn from human corpses due to mamono mana.''

### Monster Girl Encyclopedia World Guide I: Fallen Maidens | Monsterization Case Studies | CASE 07: Corruption

>Oh, God... I confess. I didn't use my body, even though I wanted this person. I didn't strike him with my desire. My sin was being ignorant of such a pleasurable thing... ah... you came again for me, huh... from now on... I swear to you and God, that I'll drown in this pleasure, and be lewdly corrupted... aah... please fill me with more thick white stuff and stain my sin pure white...
>
>—*A sister / dark priest and former human confessing while straddling a man*

Yielding to pleasure, losing to desire, and doing whatever one pleases is nothing other than corruption to the humans who uphold the teachings of the Chief God and regard chastity and abstinence as righteous.

The one who governs such ''corruption'' is a god of the monsters possessing vast power that is called ''the Fallen God.'' She regards falling, and living according to pleasure and desire as virtuous, and she uses her own subordinates, angels, and devotees to corrupt every race, whether human, monster, or other. Her religion is propagated by her angels and devotees using sex to directly instill the body with the wonderfulness of corruption and spending one's days enjoying hedonism. They basically increase the number of devotees using mostly this method, but sometimes the Fallen God directly calls out to a human heart in an attempt to corrupt it.

Among people who are devotees of the Chief God, there are those who can hear the voice of God, and use god's power to cast holy spells. Such is only possible because the devotee is connected to god through mana. Due to this connection, the will of God can be revealed, and it's possible to use divine powers. This energy link is extremely firm, but if the devotee begins to harbor doubts about God and the Order, their faith weakens, and they're corrupted by mamono mana and in the process of changing into a monster, then the link weakens tremendously. According to one explanation, the energy of the Fallen God has a very similar quality to that of the Chief God, so she can usurp these weakened energy links, and use them to call out to human hearts. The Fallen God's words are words of temptation that vividly illustrate the ecstasy and happiness that awaits after falling.

Those who listen are painted with desire, and envision a wonderfully splendid future in which they do as they want, seeking sex, becoming more and more lewd and lascivious, ultimately falling as a filthy, depraved being that exists solely for the purpose of indulging in desire. The vision of the future revealed by the Fallen God is so sweet that their faith in the Chief God is completely swapped for faith in the Fallen God. Lewd desire and sex which were formerly taboo become deeply rooted for them, and conversely, overcoming desire and living abstemiously becomes their new taboo. On the contrary, they become ashamed of themselves for having formerly been clean and pure and having had puritanical thoughts, so they have sex with men and try to fall as hard as they can, almost as if to drag down and defile their past self, painting over her with thick white mana.

Even in the case of monsterization where the devotees of the Fallen God are not involved, due to the intervention of the Fallen God's voice, one who would change into a ''succubus'' would instead change into a ''dark priest,'' and in the case of other races, as soon as they change, they awaken to the faith of the Fallen God at the same time that they change.

Human beings are animals filled with desire in the first place. The Fallen God awakens them to the desire that they possessed all along and corrupts them by making it swell so huge that desire itself becomes a core value. However, warping the values of god's servants who regard chastity and abstinence as virtuous to be exactly the opposite is something that feels almost like brainwashing.

### Monster Girl Encyclopedia World Guide I: Fallen Maidens | Monsterization Case Studies | CASE 08: Ritual

>Aah...... thank you..... I too have a beautiful snake body, the same as god..... I'm so happy.
>I can bind my beloved man with this body, and continue to be joined with him...
>
>—*Former human, girl who was a member of the snake god faith / echidna*

Races that can change human women into monsters had that ability, to begin with. However, they aren't necessarily the only ones that can change human women into monsters. Although it can take some time, there are various spells and magical rituals for changing humans into monsters that exist in the world.

One of them is the ''ritual of the snake god'' performed by the snake god faith. The snake god faith is one of the monster faiths where the monster ''echidna'' is worshiped as a god. It's treated as heresy by the Order of the Chief God. To them, the snake is the symbol of bountiful harvest, eternity, and womanhood. We can say that the form of lamia family monsters having a snake body binding men, and the motherly nature of echidna, the mother of monsters, are truly symbols of eternity and womanhood.

Also, they are symbolic of ''power,'' since they can seize the prey they desire, claim it as their own, and bind it to themselves. Not only echidna, but other lamia family monsters such as ''medusa'' and ''lamia'' also generally end up as targets of worship as relatives of god. The worshipers have peculiar values. Their children are also raised with those values from generation to generation. Along with their god echidna, they hold monsters in an entirely positive light. They desire the power to bind what they want to themselves the way that monsters, especially lamia family monsters can. Human girls brought up that way since early childhood strongly desire to become monsters themselves and acquire a beautiful, alluring snake body. Becoming an echidna means becoming a god themselves. Becoming another lamia family monster is also an act of approaching godhood. The ritual for converting such girls into monsters is the ''ritual of the snake god.'' The ritual is performed using numerous snakes.

By continuously exposing the snakes to the mamono mana of echidna and other lamia family monsters over a prolonged period of time, they can infuse them with mamono mana for future use. The ritual is performed over a special magic square that changes the body to make it easier to receive mamono mana and pleasure. The snakes infused with mamono mana are released onto the girl's body, crawling around, coiling around, and binding her while giving her pleasure. The mamono mana settles in overnight. At the same time when the girl's body changes into that of a monster, in the case that she changes into a medusa or echidna, the snakes used in the ritual join with the girl's body, becoming her hair snakes. Once the ritual is over, the girls are ecstatic that their body has changed into a beautiful snake body like that of a god. They will then immediately desire to use that body to bind the man they love to them eternally.

As for the preparation of this ritual, when young men are offered up as sacrifices, in exchange, the lamia family monsters will continuously have sex with them, and after this, the mamono mana produced from all that sex is then infused into the snakes. The higher the rank of the lamia family monster, the longer it takes for the preparation. If they're snakes for lower rank lamia, then it can be done in a few days at the earliest, but in order to produce a high-rank echidna, it takes at least several years, and could take decades, depending on the case. That's why these girls feel extremely happy and honored to be chosen for the snake god's ritual, and even more so if they're able to change into an echidna.

One point about these rituals that deserves special mention is that these rituals weren't created by the monsters. They were created by humans who desired to become gods. In this way, among the adherents of the monster faiths, there are many trials for the sake of approaching godhood. Various spells and rituals for monsterization were produced by the hands of humans.

### Monster Girl Encyclopedia World Guide I: Fallen Maidens | Monsterization Case Studies | CASE 09: Possessions

>Huh!? Why can't I take off this armor!? Damn! Damn! Oh, my head came off.....
>
>—*Dullahan that had been a human knight until only a moment ago*

In the dungeons where monsters lurk, there sleep various treasures such as valuable, beautiful ornaments, and magically enchanted armors and robes, etc. Even among such treasures, there exists some equipment such as clothing, weapons, and ornaments, etc. that is imbued with powerfully concentrated mamono mana.

This equipment is also called ''cursed equipment'' by humans. Once a human puts it on, they're unable to take it off, and the thick, solidified mamono mana dwelling within the equipment will flow into the human wearer's body to bind with the energy inside. At first, effects such as a heightened mood, and greater physical abilities, appear. Depending on what race the imbued energy belongs to, it can cause various other effects such as improved agility and a better sense of smell in the case of ''werewolf mana,'' freakish strength in the case of ''ogre mana,'' and the ability to cast ice magic in the case of ''yuki onna mana.'' However, if worn for a long time, with each use of the equipment's ability, more mamono mana flows inside. It's difficult to notice because there will be no change in appearance whatsoever, but bit by bit their thoughts and behavior will get closer and closer to that of a monster of that race. Additionally, like a monster, they'll start to feel that human men are delicious, and notice the sweet smell of energy in the air.

By the time they notice, it's already too late, and they're unable to remove the equipment. Their desire for men just keeps on swelling, and all they can do is wait until they change into a monster. Eventually, all of the equipment's energy flows into the wearer, and at that moment, the body suddenly starts changing completely into a monster. Equipment like this has been set up as a trap for humans by the monsters of the ''radical faction.'' Monster merchants disguised as humans sell them to people, and they get mixed in with the regular merchandise, so they're scattered throughout all the lands of the world.

These items are made with a special product of the Mamono Realm called ''Mamono Realm silver,'' a metal that is easily infused with mamono mana. Other than that, if items related to each particular race are used, such as collars for ''werewolves,'' armor for ''dullahans,'' or flower decorations for ''alraune,'' then it's easier to infuse mana. What's dangerous are pajamas made from ''weresheep'' wool, etc. Only a faint amount of mamono mana dwells in wool that has just been sheared normally, and it would have no influence on humans other than causing the original effect of peaceful sleep, but it's impossible to tell if there's one with condensed mamono mana mixed just by looking. If a woman were to wear it and go to sleep, then upon awakening, she would completely change into a weresheep.

Additionally, if a man were to wear one of these items, then he would gradually change into an incubus due to the mamono mana imbued in the item. In that scenario, what's different from changing into an incubus normally is that the energy generated by the man will change to be more preferred by monsters of the same race as the monster whose energy is imbued in the equipment. For example, in the case of equipment imbued with ''werewolf'' mana, the flavor and taste of the man's energy will change to suit the preference of werewolves. The scent would tickle the nose of werewolves and be more appealing to them compared to that of normal mana. No matter where the wearer went, he would be hunted by unmarried werewolves, and he'd end up getting attacked over and over.

### Monster Girl Encyclopedia World Guide I: Fallen Maidens | Monsterization Case Studies | CASE 10: Sex Change

>Hey, what's gotten into me...!? Why is it I want you so badly... this is wrong... I'm a boy, yet... hey, should I let myself get even weirder... 😳
>
>—*Former human male, boy soldier of Lescatie / Alp*

![(1) A boy having a fun conversation with his best friend. At this point, he's probably not even aware of the love for his friend hidden within his heart. (2) "T-T-This isn't weird, right!? G-Getting off your best friend is a n-natural thing, isn't it!? ...Ah! This thing of yours... smells so good.... 🤤" Even though she's bewildered, she's a monster, and the way things would turn out was probably determined from the beginning. (3) "Hey, I've become a girl for you? So why not use me more? For your sake, I'll change myself to suit your tastes even more closely! 💅 I'll become a much, much naughtier girl... 😈"](https://mgewiki.moe/images/6/6a/Alp_Z.jpg)

Normally, monsterization only occurs in females. Since monsters are exclusively female beings, males don't change into monsters. In the case when a male receives mamono mana in his body, regardless of the race of the owner of the energy and the method of energy infusion, he will only change into an ''incubus.'' But, very rarely, a male who should be an incubus may sometimes change into a female monster. The huge exception is the ''alp.'' Alps are incubi who strongly desired "to become female" or "to be joined with a male" that unconsciously used the mamono mana dwelling within them to destroy their own essence generation function. By losing all essence and being completely stained with only mamono mana, they are changed into monsters. They change from being human males to being incubi, and from being incubi to being monsters, in that sort of order, but since the transformation can occur immediately after becoming an incubus, in most cases it probably looks like those who changed into alps changed directly from human males into alps.

Unlike the cases when a female changes into a monster, their morals, and thinking don't suddenly change. Instead, the heart, values, memories, and personality of an alp, everything except the body, remain the same as those of the original male. In spite of their body changing into that of a female, they will probably only acknowledge themselves as male. Even if the desire they possess is strong, often it may be hidden deep at the bottom of their heart, and the individuals themselves may not be aware of it, or they may have just been pretending not to notice it. They will be bewildered by the gap between a male heart and a female body. Even if their heart is male, their body and instincts have become those of a splendid monster. A monster's body throbs with desire for pleasure and essence. A monster's instinct naturally craves human males. Though bewildered, they are fated to eventually lie with their beloved male. Once they copulate, learning the taste of a woman's pleasure and mana for the first time, they'll no longer be able to suppress their monstrous urges. As they have sex, again and again, they change to become even more monster-like.

Alps mainly change into one of two types. The first is one that retains a male heart while changing to become more monstrously lascivious. Their male values and thoughts remain intact, and they'll even treat the male who becomes their husband lightheartedly as a friend, no differently than before. They already acknowledge that having sex with another guy is a natural thing because they're in love. They'll likely desire to have fun hanging out and getting off with their beloved best friend day after day. Even when they invite a guy for sex, they do it lightheartedly as if inviting him to hang out. The words they used to use to invite him to hang out when they were human "What are we gonna do today?" probably have taken on a completely different meaning, "What are we gonna do today?," now that they've changed into a monster. Also, since they were originally male, they know all about male tastes and weak points, so they can enthrall a male with pleasure that's different from that of other monsters.

The other type consists of those who awaken to the powerful joy of being a woman while having sex with a male. Unlike the other variety of alps who mostly have an androgynous appearance, their bodies change to become even more lewd and womanly. Their butts and breasts grow big and soft the way men like, and their facial features also change to become more feminine and beautiful. Their heart, values, and personalty, etc. also change to become womanly. Since they're overjoyed to be a ''woman,'' they're even more womanly than those who were women to begin with, and they may possibly grow into a more lustful and lewd succubus (inma) than those who were born a succubus to begin with. Also, since their memories and values from when they used to be male don't disappear, they have a firm understanding of what a man's preferred ''ideal woman'' should be like. Their ''womanly'' figure will turn out to be the kind of ''womanly'' figure that a man would prefer.

In this way, we've broadly divided them into two types, but they don't necessarily cleanly split into one of these two types, and there are alps that vary greatly due to individual differences. Among them are also those who retain androgynous looks, while their heart alone has grown feminine, and those who have a full womanly figure while retaining a male heart. Furthermore, since an alp's body has completely become that of a woman, it's also possible for them to produce children with a man's semen.

What it comes down to is this. Alp is just a moniker for those who exceptionally changed from an incubus into a ''succubus,'' so they are essentially succubi. For that reason, the children born will turn out to be ordinary succubi, not alps.

In this section, I've written in detail concerning alps, but there's another possibility for a male to turn into a monster, ''skeletons,'' which are bones reanimated by mamono mana. They can also be born from the bones of a male, and retain memories from when they used to be male, but they get distorted in the following manner: they will believe "they used to be a woman when they were alive," and that the man who was their best friend when they were alive "used to be their lover."

They're beings who changed from ''what used to be a man'' into a monster, but when it comes down to it, they're supposedly just golem family monsters produced from bones as a material, and for that reason, scholars have a divided opinion over whether or not this case of monsterization should actually be regarded as a sex change.

### Monster Girl Encyclopedia World Guide I: Fallen Maidens | Monsterization Case Studies | CASE 11: Food

>This pink fruit smells nice, and it's very sweet and tasty! 😋 Huh... there's some kind of nice smell coming from you too... anyway, it seems very tasty... 🫦
>
>—*A certain inn's sign girl / human*

Food gatherable in Mamono Realms grows rich from absorbing mamono mana in abundance, and there is a variety of special produce made from it. The fruits, vegetables, livestock, and fish produced in mamono realms are all delicious and very highly nutritious compared to that of the human realms. However, since it contains plenty of mamono mana, if one eats the produce, again and again, she will eventually end up changing into a monster.

Out of all the special produce, ''prisoner fruit'' is especially famous. Prisoner fruit is a heart-shaped fruit that ripens on mamono realm trees that is a lustrous pink color, almost like a gemstone. There is soft, milk-white pulp packed inside the skin that's so thin it's almost transparent, and poking it with a finger would cause sticky juice with a sweet fragrance to spill out, stirring the appetite. Upon eating the pulp, it would melt in the mouth-filling every inch of it with a mind-blowing sweetness. As the name suggests, this fruit has a powerful aesthetic effect. It is familiar among monsters as a standard dessert. By consuming this fruit, monsters' bodies grow more alluringly attractive so they can better ''imprison'' men.

This fruit is a staple among monsters, but when humans eat it, it suddenly causes an extremely huge change in the body due to the effect of the mamono mana. If a human woman eats it, first the woman herself will become a ''prisoner'' of this sweet fruit. She'll become half dependent on it and end up seeking the fruit. When a human woman continues to eat this fruit, in the first stage, an ordinary beauty-enhancing effect is apparent, and each time the woman eats the fruit, she'll gradually change into the beautiful figure preferred by men.

In the second stage, not only changes in looks, but also psychological changes begin to appear. Regardless of the woman's intentions, her behavior and gestures will naturally change into the kind that is preferred by men. Eventually, even her casual utterances and gestures will change to become arousing and seductive to men.

Even her gestures when eating the fruit will become alluringly sensual. In the third stage, pheromones that attract men will start to be released from the woman's now beautiful body, and the men around her will already be becoming her ''prisoners.'' The woman herself will become extremely interested in men and sex. Her head will become full of desire for them, and her mind will be dominated by thoughts that are almost just as pink in color as the prisoner fruit. A woman in this state will sense a human man's essence as having almost the same sweet fragrance as the fruit, and men will appear as delicious as the fruit, or perhaps even more so. In the final stage, regardless of still being human, she will be under the control of thoughts characteristic of a monster, and she'll attempt to seduce and copulate with men, just like a monster. Once she's copulated with a man and obtained his essence, all of the mamono mana that had accumulated in her body from eating prisoner fruit up until then will blossom all at once, and she'll transform into a succubus.

Women changed into monsters by this fruit tend to continue to eat it periodically even afterward. Perhaps for that reason, their power to ''imprison'' men is mighty, and sweet-smelling pheromones that imprison men are released from their body. Due to this, they're able to ensure that the men who become their husbands will be completely preoccupied with them even more so than other monsters.

Additionally, while these fruits are easily obtainable in mamono realms, other than that, they also ripen in the trees of lands that are on the verge of becoming mamono realms, and monster merchants sell them. They're normally extremely hard to obtain for humans, especially people living in anti-monster states. In spite of a situation like that, there's no end to the number of people who become prisoners of the fruit and change into monsters. It is said that monster merchants slipping in disguised as humans who continue to provide the fruit at low cost are to blame.

![The soft yielding flesh of the ''Prisoner Fruit'' is sweet, delicious, and drips sweet smelling juices to tempt the palate of women while the flavour entrances](https://mgewiki.moe/images/4/4e/FM_Case11_1.png)
![Just one bite is enough for the fruit to captivate. From this point on this inn keeper's daughter is going to change in a big way](https://mgewiki.moe/images/2/20/FM_Case11_2.png)
![Having continued to eat the ''prisoner fruit'' she has entered the second stage. Her smile and mannerisms have become bright and cheerful making her the inn's poster girl](https://mgewiki.moe/images/b/b4/FM_Case11_3.png)
![Still eating the ''prisoner fruit'' she finally enters the third stage. Her smile has become completely enchanting and she captivates even the most chivalrous men as the inn's idol. She begins to act like a monster girl enticing men with the way she acts; no man can resist the lusts she incites](https://mgewiki.moe/images/b/b5/FM_Case11_4.png)

### Monster Girl Encyclopedia World Guide I: Fallen Maidens | Monsterization Case Studies | Non-Human Monsterization

It's not just humans that change into monsters. mamono mana can change all kinds of races into monsters, and, at times, even gods and material objects. In this section, let's introduce that sort of monsterization of ''non-humans'' just a little bit.

#### Monster Girl Encyclopedia World Guide I: Fallen Maidens | Monsterization Case Studies | Non-Human Monsterization | Elves

A type of people that live deep in the forests and build peculiar villages. They're also called ''forest elves.'' They are a pure and proud race, but they are hard-headed and stubborn. They are ascetic, and extremely negative towards sex and pleasure. They regard humans, monsters, and all things related to sex and pleasure as filthy and inferior, and they despise them. Since they have high magical energy, it's much more difficult for mamono mana to bind to them compared to humans, and monsterization is extremely gradual. They won't completely become monsters just from having sex with monsters. mamono mana arouses their bodies, eventually leading to a state where they have lewd desires and fantasies. Then, upon receiving a man's sperm, they completely change into monsters. Elves are sensitive to magical energy, and at the stage when one has been corrupted by mamono mana, everyone around will notice it, and banish them from the village, so chain monsterization and conversion of elven men into incubi rarely ever happens.

After monsterization is completely finished, they become extremely lustful and lewd monsters, almost like a backlash or something, from everything until that point. When humans who think of sex and pleasure as dirty things change into monsters, in most cases, that hatred disappears, and they start to recognize it as a wonderful thing. But for most elves, sex and pleasure remain as filthy things along with humans. However, in a monster-like fashion, they start to deeply love those filthy humans. As if ashamed of how clean they had been until then, they wish to be defiled with filthy lust and milky white semen, falling to become a being just as filthy as their beloved men. For them, it is an unbearably joyous thing. Just as they were once proud of their purity, it is said they become proud of their filthy, indulgent lives as monster ''elves.''

Additionally, there is a matter that is often misunderstood. That is, even if ''elves'' change into monsters, they don't become ''dark elves.'' These two races were entirely separate from the beginning.

#### Monster Girl Encyclopedia World Guide I: Fallen Maidens | Monsterization Case Studies | Non-Human Monsterization | Fairies

A race that has extremely tiny bodies, and they are not monsters to begin with. They're a childish race that likes fun things. They spend every day playing and having fun. Since they are balls of magical energy, they are easily influenced by mamono mana. By playing with monsters that are childish like themselves, they get showered with mamono mana, and soon change into monsters. After becoming monsters, they still have the same childish appearance and still love to play, but in monster fashion, they end up mainly choosing human men as their playmates. And then, after being taught by their monster friends, or by their own monster instinct, they'll try out very pleasurable forms of play.

They have tiny little bodies that look way too small for a man's penis to fit inside, but with a monster's durable body; they can swell up their stomach and receive a man's penis. It looks painful, but the fairies don't feel any pain. Even when they play in this state by having a man seize their tiny body and shove his cock in and out wildly, for them, the only thing induced by it is wild pleasure. Many fairies live in the Fairy Kingdom ruled by the Fairy Queen. The Fairy Queen and fairies want to have more fun and experience more pleasure. Many monsters are accepted in the Fairy Kingdom, and the fairies are changing into monsters one after another. In the not too distant future, the Fairy Kingdom will become a Mamono Realm, and the fairies will all become a type of monster.

#### Monster Girl Encyclopedia World Guide I: Fallen Maidens | Monsterization Case Studies | Non-Human Monsterization | Angels

Lesser divinities that are merciful and abstemious servants of the gods. Since they have extremely strong magical energy, they don't completely become monsters right away. Many of them retain the same sense of self, and when mamono mana induces lust and makes them do dirty things with human men, they just think of it as being part of an angel's duty to give happiness to people. In the same way that the Mamono Lord is connected to the monsters through mamono mana, the angels are connected to the Chief God through magical energy, and it is possible for angels to hear the voice of God.

However, in the case where they become self-aware of their affection for human men, that magical link is usurped by the ''Fallen God,'' and their indecent desire for human men is made to swell. Once a man lusts for them, it is said they end up being reborn as ''fallen angels,'' servants of the Fallen God who just want to fall together as ever more indulgent, lewd beings.

#### Monster Girl Encyclopedia World Guide I: Fallen Maidens | Monsterization Case Studies | Non-Human Monsterization | Gods

Mamono mana can corrupt even a god at times. ''Poseidon, God of the Sea'' and the ''Fallen God'' are gods that became monsters, and using their vast power, they have created Mamono Realms in other dimensions, changing the environment itself to make an ideal world appropriate for monsters to live in. If even more of the gods end up falling, the Mamono Lord's ideal world will be realized, and then the arrival of the end of the gods will be rapidly hastened.

#### Monster Girl Encyclopedia World Guide I: Fallen Maidens | Monsterization Case Studies | Non-Human Monsterization | Beasts

It is extremely rare for a mere beast to change into a monster. They will never change into monsters just from simply being showered with mamono mana. However, mamono mana reacts to love and lust, and it is extremely easy for it to become fused with those. For that reason, in the case of dogs and cats, etc. that are kept by humans and share a strong bond with their masters, a beast may change into a monster. Those who are called ''kettoshii'' and ''kuushii'' may have a humanoid appearance, but their forms are entirely covered in fur. Compared to other beastman type monsters, their appearance and biology are closer to that of beasts. From the time when they were merely beasts, they had a love for their master strong enough to change themselves into beasts, and a bestial desire to mate as male and female. They want more than anything to mate with their beloved master and bear his children.

#### Monster Girl Encyclopedia World Guide I: Fallen Maidens | Monsterization Case Studies | Non-Human Monsterization | Material Objects

Since material objects are inorganic, it is easy for mamono mana to dwell within them, especially things that were designed as receptacles for mamono mana, and human-shaped things. If there are more thoughts concentrated on an object, it becomes easier for mamono mana to dwell within it. ''Golems'' and ''gargoyles,'' etc. are also such with life within them. The magical material-type monsters are almost entirely fueled by the energy of human men. They maintain their bodies through sex with human men.

Also, in Zipangu, spirits of things used and taken care of for a long time that have feelings of gratitude, or conversely, spirits of things that were abused and discarded that have feelings of resentment may manifest as ''artifact spirits'' and start moving. These result when the strong emotion dwelling within objects is fused with mamono mana, causing them to change into monsters. As for artifact spirits, in either case, their goal is ''to be used'' by humans. Of course, they can be used as ordinary tools, but after becoming monsters, they all obtain a devilish body without exception, and a bigger goal for them is to get human men to use their bodies and get off with them.

In this way, various other living things besides humans may change into monsters. However, when they change into monsters, their race is fixed. If they're elves, then they change into ''elf'' monsters. If they're fairies, then they change into ''fairy'' monsters. Basically, even when an elf is bitten by a werewolf, they of course still change into ''elves.'' Unlike humans, they individually have strong magical energy within them, so that's one of the reasons why, but the reason why only humans can change forms into various monsters might also be because the current monsters have become closer to ''human'' than anything else so that they can couple with human men.