Yoshiten
From Bible Black Wiki

Yoshiten's lewd drawing of Takashiro.
Yoshiten (よし天) is a male senior Academy student and an unseen character mentioned in Bible Black: Only.
One of his papers is checked by art professor Hiroko Takashiro right after student Habuo's. Yoshiten has drawn a small pornographic picture of her at the bottom of his paper. It prompts Takashiro to masturbate while thinking about having sex with her students in a classroom, possibly with Yoshiten as well.
Trivia
- His name is likely a reference to Bible Black's animation director and character designer Yoshiten.