[spoiler] I'm looking for a mango where the main guy goes back in time to his old body he has a brother it's a martial type manga and I think he's supposed to be evil manga may or may not have been canceled I think the things they use are called gu and I remember there was this one part where the instructor sent paper fetch him right before he broke through so he killed them I believe and then went to class covered in blood please help

The Blood Reaper

Maybe Reverend Insanity