Encyclopedia Entry
The earliest stage after a human woman transforms into a succubus by having mana flow into her body through sex with a succubus. Just like the succubi, they absorb essence through having sex with human men, sustaining themselves. As for how they differ in outward appearance from succubi, they have comparatively smaller horns since they’ve only just grown in, small, translucent wings and tail, and hair covering various parts of their bodies. They use magic in order to make their bodies more appealing so that they can seduce men. The hair is there to protect their bodies during this time.
When a human woman changes into a succubus, the first thing that happens is that her lust and the sexual sensitivity of her body skyrockets to an unbelievable level. Since they’re starving for essence, they become overcome with an intense hunger. Women who’ve only just become monsters still have their human values, but with the monstrous body that’s hot for men, and the intense feeling of hunger, the human mind can’t hold out. Driven by desire, they end up attacking human men.
Once they get a taste of the devilish pleasure, they become its prisoner. Their human values crumble away. They drown in it, seeking men and pleasure with all their heart. As they gain human essence in this way, their little horns, wings, and tail grow bigger, and their heart becomes more and more lustful, completely transforming into a succubus. Even after becoming a succubus, their base personalities and memories are all still the same from the time when they were human, but their values change in whatever way is needed to become those of a succubus. They will start to aggressively attack men, in pursuit of essence and pleasure.
There is no known method to change a woman who has become a succubus back into a human. In the case that one’s love ends up becoming a succubus, he should give up on saving her and just run away immediately. If not, he’ll probably be taken by her to a Mamono Realm, and be forced to frequently copulate with the bewitching, lustful demon that she has become for the rest of his life.