Lee Chang obviously went through something very traumatic and I don't know whether he killed all those people or not but his mind is definitely broken and he's fighting to stay sane. Imposter Hwi appears around the time of the deaths too, maybe Chang created this new Hwi since he keeps telling Chang he'll be okay if they stay together and everyone outside thinks of him as a murderer. Something I recall is the moon, whenever Chang gets these weird memories he sees the moon or the sky, so whatever traumatized him definitely happened at night. Probably all this is only happening in Chang's mind, maybe he's in a coma or something like that, but he's definitely having a real hard time coping with something he did or saw.
Lee Chang obviously went through something very traumatic and I don't know whether he killed all those people or not but his mind is definitely broken and he's fighting to stay sane. Imposter Hwi appears around the time of the deaths too, maybe Chang created this new Hwi since he keeps telling Chang he'll be okay if they stay together and everyone outside thinks of him as a murderer. Something I recall is the moon, whenever Chang gets these weird memories he sees the moon or the sky, so whatever traumatized him definitely happened at night. Probably all this is only happening in Chang's mind, maybe he's in a coma or something like that, but he's definitely having a real hard time coping with something he did or saw.