Kōsuke Edogawa

Kōsuke Edogawa (江戸川耕助, Edogawa Kōsuke) is the classmate/best friend of Kiyotaka Yoshino in class 2-1 who is a masochist.

Etymology

The name Kōsuke means "plowing" (耕助).
Kōsuke's surname Edogawa means "bay, inlet" (江) (e), "door" (戸) (to/do) and "river, stream" (川) (kawa/gawa).