|Job||High School Student|
|School||St. Chronica's Academy|
|Manga Debut||Me and Slave and Blue Days|
Tanashi (Tanashi) is a classmate of Sena Kashiwazaki's who makes an appearance in volume one of the Boku wa Tomodachi ga Sukunai: Kōshiki Anthology Comic series.
Tanashi has puffy, dark-colored hair and was seen wearing his school's uniform. During his appearance, he was seen a ballgag and blindfold.
Tanashi is one of the students of St. Chronica's Academy that has an odd obsession with Sena Kashiwazaki. During his short appearance, he was seen wearing a ballgag and blindfold while allowing Sena to sit on top of him. Sena mentions that he always begs for this as a reward.
- Slave 
When Yozora Mikazuki goes to have Sena fill out her club application, Tanashi is seen letting Sena sit on top of him. After Yozora leaves, Sena tells him that he can go home now as she's going to the Neighbor's Clubroom.