Lesser Succubi are a transitional kind of monster girl, when a monsterized woman is part way through her transformation from human to succubus. In this state, the overwhelming lust and thirst for semen are totally new feelings to the corrupted woman, and her freshly supercharged erogenous zones are extra-sensitive, so ironically the lesser succubi tend to act even more frenziedly hedonistic than their final forms.
It is not known whether all monsters, or just the succubus family, or just the succubus in particular have transitional forms like the lesser succubus. There is at least one analogue from elsewhere in the encyclopedia: the kitsune-tsuki, an intermediate form on the way to a youko or inari foxgirl. It's also not clear how long the lesser succubus form tends to last. In some passages it's implied that the transformation is completed by just having sex once, but on the other hand kitsune-tsukis are said to often remain in that form for their entire lives, so maybe lesser succubi are the same .
If a monster girl is positively overloaded with demonic energy during her transformation, it's possible to go straight from human to succubus without passing through lesser succubus at all, which is what happens to Wilmarina Noscrim in Fallen Maidens .
The earliest stage after a human woman transforms into a succubus by having Demonic energy flow into her body through sex with a succubus. Just like the succubi, they absorb spirit energy 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 spirit energy, 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 spirit energy 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 spirit energy 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 Demon Realm, and be forced to frequently copulate with the bewitching, lustful demon that she has become for the rest of his life.
- ↑ Kitsune-tsuki profile: "Many kitsune-tsuki spend their entire lives as kitsune-tsuki, however, although it is extremely rare, in the case of individuals who were originally powerful by nature, or those who had sex with a man countless times and stored a vast amount of demonic energy, youko-like kitsune-tsuki have transformed into youko and inari-like kitsune-tsuki have transformed into inari."
- ↑ Druella's profile: "This explains why “Wilmarina” shows up in this book evolved beyond a lesser succubus into a succubus, and why “Francisca” is more powerful than an ordinary roper."