I don't know. I think a lot of the characters have a bit of trauma. Also the bodyguards don't really have a say in the matter they are just promised to serve the heads of the main branches of the family. I think Lau and Fu Rin didn’t really want to be bodyguards it was decided for them. Although Lau is friends with Xin I don't think he likes that he is in this master and servant type bond that Xin has power over him and Lau is forced to protect him. It's like if you were a kid and you were told you were supposed to be a body shield for this rich kid that was your destiny. Over time you befriend the rich kid, but the resentment is still there because he is rich and powerful and you didn't choose to serve him. So it makes sense that Lau rebels. Chin is a bit insane because he is from one of the lower branches of the family and he feels threatened by the head family because of how much power they have.
Why is everyone insane in this Mahnwa?