Someone said « I'm staring to think the one who killed his father is himself. I think his father was turning into a zombie and he kill him (u know classic moralistic cliche) however the shock was to much for him and that's why he now has amnesia and PTSD for the trauma, this also would explain why in his sonambulismo (don't know the word in eng) he tries to hurt himself, like a response to "clean" the evil..
Well that my theory since teach is so moralistic ╮( ̄▽ ̄)╭»

Bro teach is such an unreliable narrator like i do not believe guwon killed his father like he def isn’t right in the head but neither is teach its like everything either one says is just lies or they just genuinely don’t remember the past