The Chief of Yagiri Pharmaceuticals and sister of Seiji Yagiri. She harbors feelings for her brother. She is behind the recent human hunting in Ikebukuro which involves kidnapping people whose disappearance would not be noticed for unknown experiments. She seems to rely on Shinra for some tasks, including keeping their secret. She doesn't like the fact that Seiji is in love with Celty's head. She wants to get rid of what she calls "that thing." After Yagiri Pharmaceuticals ends up merging with another company, she makes a deal with Izaya and becomes his secretary.