The fembo- Alp are monster girls that are generated when an incubus (corrupted male human) has in its subconscious or conscious the desire to be a woman or be with a man. This causes the power that an Incubus normally possesses to be redirected towards itself, causing a self-destruction of its own essence. And without essence, there is nothing that distinguishes a human as human, and because everything is mamono mana, the subject becomes a monster girl.