Doppelganger

Encyclopedia Entry:
A monster that is thought to be born from a fusion of the lingering regret of those who lost love, and the monster’s demonic energy. They reveal themselves after being drawn by the lingering regret of men who were rejected by the women they loved. They don’t have a fixed form. Instead, they read the minds of human men, and appear in the form of a woman that the man had a one sided crush on. Not only do they look like her, they also take on the woman’s memories, personality, and abilities, making them their own.

However, their form is modified to be based on the memories and ideals of the man who was targeted. For example, even if the woman a man had feelings for was “nice on the surface, but malicious and scheming on the inside,” she becomes a woman matching the man’s ideal that is “pure and gentle, even in heart.”   Also, since the doppelganger herself has feelings for them man, the reason they transform is “to become the man’s ideal woman so he can’t help but love her.”   Most men aren’t able to resist the temptation of a doppelganger, and they’ll have sex and release spirit energy on the spot when seduced. Even afterwards, they continue to be the man’s ideal lover, and continue to offer love and pleasure to the man.

They are always transformed, and they never show their true forms, except when they lose the magical power to transform on the night when the moon can’t be seen. Their true form doesn’t look anything like the guise of the ideal lover which they had assumed: a plain little girl draped in black. Since they know that the person the man loves is the woman whose form they borrowed and not them personally, they fear being revealed for who they truly are and being hated by the man.

For that reason, when night comes, they hide themselves somewhere so that they won’t be found by the man. But since they’re so in love with the man that they can’t help it, they always hide nearby. If the man was to search thoroughly, he could probably find her. It is said that when a man truly falls in love with a doppelganger herself and not the “ideal girlfriend” whose form she had borrowed, they completely lose the ability to transform since they can’t transform into themselves.