Responses
I think since he doesn't really remember his life but just feels like he had a life outside, it must be part of the bug or something. Ko matter how long it has been you don't forget everything. All he knows is that he has a cousin (that he has no attachment to) and that this is a game. Very superficial stuff.
I got a CRAZY thought.
What if ML is the player from outside and MC is an NPC who gained consciousness. ML must be a developer so he came to repair the bug. That is why MC can't kill the killer cuz he doesn't have the specs nor can any other characters whereas ML feels like he has control over it.