A student of Seiin High School and Mikihiko's younger sister. She collaborated in her brother's research as a test subject, and became friends with Esther. She lost her life in an accident during the research work.

Hirumi and her associate Hishigata are part of DA, and are in search for the perfect mind and body. However, the two have their own plans and are just using DA for their own ends.

She was apparently a normal high school girl at the same time as Esther was tricked into becoming a supervisor in Hishigata's research into how esper powers reside in the human body. In spite of that Hirumi and Esther became friends. Hirumi later dies and Esther resurrects her, much to Hishigata's relief. However, she later discovers that Hirumi became possessed by the evil spirit Taowu.

(Source: Wiki)