Sayuri Higuchi
Sayuri Higuchi is Morito Hayama's former mentor and a prime antagonist of Gun X Clover series. Formerly as Morito's mentor, Sayuri taught mercenary skills to Morito before his rise as one of the 13 Master Rank Mercenaries and also the only mercenary alive capable to injure Morito. While being rouge for her notoriety, Sayuri is also a founder of the Child Room and responsible for conducting vile experiments of children for her Child Army. With the combination of her abundance experience in warfare, instability of madness and possessing the Dead Language, Sayuri proved to be Morito's most dangerous and vicious enemy.