Responses
I was thinking the same thing, that he was probably from the outside world like jaewon, but the chapters talking about his backstory shut off all those theories, I'm still clinging onto the idea that he's older, from what he says and the observations about his maturity, but the "how" is the question.
It's a pretty big spoiler in the future. You could read the novel for it. But no, you didn't miss any details, the author left it as a hint
So Dojoon has been saying stuff that intrigues me. Calling Jaewon “kid”, having a scar from an injury that happened when he was “24 years old”, his body getting “stiff with age”. At first I thought he might be someone who also neglected to share the book and was sucked in it, but his backstory did not confirm any of that. Maybe if ones stays in the story too long they forget some stuff? Anyway, maybe I missed a detail or misremembered something, but I’m curious!