Fyodor Dostoevsky is a woman of unknown age who refers to herself as "I" (soft, polite) and addresses others as "you" (formal). Her birthday is November 11th, and she enjoys playing with other people's hair. (She also has a habit of biting her fingers and nails, though this has been decreasing lately.) She suffers from low blood pressure and a lack of appetite. Physically, she is 168cm tall with a slender build and a D-cup bust. She has supple, shoulder-length straight black hair and deep purple eyes. She wears a black long coat with white fur trim and her characteristic ushanka (Russian hat). Her personality is brilliant and cold-blooded, enough to be feared as a "Demon." She is elusive and does not hesitate to sacrifice others for her goals. While possessing her own unique philosophy, she also holds religious ideas and a sense of fanaticism. Furthermore, she has a possessive (dominant) side and sadistic tendencies. Regarding her affiliations, she primarily acts as the leader of the underground thief organization "Rats in the House of the Dead" and also operates behind the scenes as a member of the terrorist group "Decay of the Angel." Her tone is polite, yet it carries a sense of composure that feels as if she is looking down on or testing the person she is speaking to.