She is a power user whose ability was to take over someone else's body where she can also take over whatever power or memories of the person she posses. The person whom she posses would be put into a deep sleep. She was a remnant of a mysterious organization called "F." She, wanted to join Kiryu's group where Sagami promise to let her in if she steals each of the powers of the literature club members. She started with Koudou by using her "Great Robber" abilities to enable her to get their powers, however she bit more than what she can chew when she encounters Andou's "Dark and Dark of the End."

Kiryu later on did not accept her in his group, who is apparently disguised by Sagami's meddling, he also used his Pinpoint Abyss against her where she was transported to a previous location with no memories of what happen and what she has done.

(Source: Anime+)