A young underground doctor who lives with Celty and is also her lover. He stays mostly indoors and wears a white coat even when not working as a doctor. He went to the same primary school as Shizuo, and has since then been interested in his unlimited strength in times of anger, in fact he rather enjoys when Shizuo makes use of his strength. His father was a doctor and since childhood, he has participated in surgeries with his father, the most notable an autopsy on Celty. He went to the same middle school as Izaya and has been friends with him since then. He enjoys to some point the constant fights between Shizuo and Izaya.