He was a man with elegant features, thick eyebrows, a beard and a mustache. He had short hair slicked back and, like most Investigators, wore a formal suit and white coat.
He is part of the Atou Squad, fighting the White Suits alongside the Quinx Squad and the Ooshiba Squad. He watches Haise Sasaki's fight and later the murder of his squad leader, Daisuke Atou. Later, he himself is killed by Seidou Takizawa.
- Akai was modeled after one of the 20 winners among the applicants to the ghoul investigator recruitment campaign. He is associated with "mustache" (口髭, kuchihige) in the operation reports attached to the chapters.