NPC survives a game event and discovers he is just an npc within a game world where his body can be taken control of without his permission. He later finds out he is not the only one and heads towards the crack within the system where others like him rests. He gets strong through his adventures and makes a 'player' his friend(?). But when asked to talk about the 'real' world, he later finds that everything about it became nothing. Somewhere along those lines... yeah.
i became the tyrant of the defense game , it was hinted multiple times and there was a whole arc about mc's existential crisis.