Nezumi is an intelligent, cynical boy around 16 years of age with a dark past. Four years ago, on his desperate run from No.6's police, he by chance found a house with an open window and went inside. Wounded and dripping wet, he met the room's occupant, Shion, a boy roughly his own age. Nezumi was shocked when Shion, despite understanding the danger of helping him and the lack of potential reward, treated his wound and sheltered him for the night. The next day he escaped to safety, and now lives outside of No.6 in the West Block. When he learns that Shion is being forcibly transported to the Correctional Facility, he risks his life to save him. Together they escape to the West Block, where Nezumi lives by himself and allows Shion to stay with him. Nezumi usually hangs out alone and leaves Shion at home, he used to be a loner and Dog Keeper hints to him that he changed because of Shion. Nezumi is a well-known actor/actress under the stage name Eve and is talented in singing, acting and dancing. His home is filled to the brim with books, most of which are classics. He often quotes these books on the spot (specifically Macbeth and Faust). He is a skilled fighter and has very honed 'street smarts'. He despises the City of No.6, calling it a "parasitic city" and has spent years trying to find a way to destroy it. Later in the story, we find out that the government of No.6 perpetrated in the genocide of his people and he is sole survivor of his village.