ArtemisFowl's manga / #yakuza(3)

A boy and his high school teacher get into shenanigans because of past and present ties to the teacher's yakuza history -- that history being that the teacher is heir to her yakuza syndicate's throne. Because of this interesting upbringing, the teacher is well suited to this school of delinquents, whether the students initially know it or not. Boy, are they in for a surprise... ~Chapter 'Gokusen Halloween Special'

Welcome to Tokyo Crazy Paradise, the alternate future of Japan's capital, Tokyo. Born into a police family, baby sister Tsukasa gets raised as a boy in order to protect her from the harassment and free-for-all atmosphere of dystopic future Tokyo. Years later, still living as a boy with her older brothers (but without their parents, as they were killed), Tsukasa gets involved with stone-faced Ryuuji, born and raised as the successor of a yakuza family. Once she becomes his bodyguard, things start to unfold, and even in Tokyo Crazy Paradise, not everything is what it seems... ~Chapter 110