Ok so like Anteris taught Serenity how to fight in the first place but then how he got obsessed is when he actually saw her fight her first battle against an organization after that Serenity noticed the way he was acting and stepped down as his pupil (stopped being his student) in order to find a new teacher. All in the book I'm making and yes I like writing its about how Serenity became a sword fighter.(became lazy making the book /*^*)/ still at the beginning)