Takatsuki Michiru

The main character's ex-girlfriend. She is beautiful, pretty, charming, and always has an endless supply of men.

She seems to be aware of this, too, and is always harsh in her criticisms and condescending to others.

She is severely mentally ill, an attention seeker, and has an egoistic, self-centered side.
She is unable to forgive those who betray her, and is harsh towards those she considers her enemies.