Why do I have a feeling it was the teacher that killed his own dad? And Guwon saw it happen. It's been a while since I read this story. Guwon might have said he was the one that killed the dad. But what if his words had a double meaning? He said in the latest chapters that the teacher and him are the same/alike. Therefore it wasn't actually Guwon, it was the teacher that did it. But since they are alike it's as if Guwon saw himself in the teacher when it happened. But since he switches personalities, when the "weaker" side of the teacher showed up Guwon immediately lost interest and started treating him the way he does with everyone else.
Idk Im most likely very wrong. All I know is that the teacher has definitely gone crazy at some point and killed or hurt someone when he's blanked out.

I'm crossing everything that teach regains some memories or has a flashback next chapter, im so fascinated by him! why didn't he react to the gun, at all? why does he sleepwalk so frequently and why does he get violent during it?