Based on the IMDb plot summary and AsianWiki profile , here is an informative guide to the beginning of this dark revenge story:
: The homeroom teacher, Kyoko Minami, is portrayed as cowardly and indifferent, refusing to intervene despite the obvious abuse. (Dramacool-SUB) Liverleaf Episode 1
(Hiroya Shimizu): Another transfer student and Haruka's only friend and emotional support. Based on the IMDb plot summary and AsianWiki