The mysterious girl is a girl who is seemingly possessed by a Greed.
The mysterious girl has long and wavy light colored hair. While she is a Greed her eyes become that of a Greed with black sclera and white pupils.
The mysterious girl acts like a typical girl and has grown close to Shigeo for some reason. She is unaware of her Greed side, having no recollection of what happens when she is a Greed. While she is a Greed she uses information synchronization to speak. Her Greed side has no qualms with killing, though she did apologize to the rat when she killed it and told it that she didn't dislike it.
Unknown Power: The mysterious girl is shown to have some sort of power, such as when she did something to Shigeo when they first met and later seemingly causes him to fall asleep. Shidou Izaya believes that she is a natural born sigil user.