|Full Name||Tatsumi Koutarou|
|Affiliation||Public Morals Committee|
|School||First High School|
|Year/Course||Year 3 Class C Course 1 - AD 2095|
|Voiced By||Kenji Hamada (Anime)|
|Novel||Volume 1, Chapter 3|
|Anime||Episode 3, Enrollment Chapter III|
When he met Tatsuya he underestimates him because he was a Weed, but after Mari informed him and Sawaki Midori of Tatsuya's victory in the mock battle against Hattori, he recognized his potential.
He is often teasing her, although his words may be construed as disrespect, especially since she's the Chief of Public Morals Committee. During his first meet with Tatsuya, he repeatedly called Mari Nee-san, which later earned him a hard hit on his head with a rolled up notebook.