Review Detail of Rain_Sinner in One Piece: Kamui

A shameless author reviewing his own work here, I'm still new here, and if any of you guys have any suggestion or critics, please feel free to give comment ^_^. The Mc at the start would be strong against the weak and weak against the strong. He would use provocations, dirty tactic and everything else to fill his loopholes in battle method, and as for harem.... Most One Piece FF has harem on it, but Idk yet >_<