I don't think Guwon was pretending. I think he truely is learning what it means to be human. Like he has no clue or idea of morality so he's this big powerful being with no sense of right or wrong and everyone's been too scared to try to fix his skewed sense of equality thing and its got him this far. But teach stands up and tells him straight up even when he's scared, he always has, so I think it's got him "excited"? Ultimately I have no clue what guwons goal is and why he wants this town, smut aside, I'm curious where this story is headed.
Also teach might not be as "morally correct" himself as he believes. His blank memories are maybe him protecting himself from what he's done and feels guilty for. The first chapter seemed to allude he was protecting himself from someone, maybe father?
What was up with that scene after the confession saying that he’s got it? Does that mean he’s just pretending all this time?