although it is true that the Fourth Wall was formerly the dokkaebi king, Kim Dokja didn't know that even until the end as far as we know.
Edit: Now that I think about it he probably did know after reading the final revision of Ways of Survival but point still stands since he only knew about it at the end.
@pospani don’t link to illegal translation sites unless you want them taken down. The official and legal translations are on webnovel.com. If people want to read it for free they can either google or ask for it to be dm’d but linking to an illegal site on a public forum may get all of them ceased and desisted.
@7Lotus well, there are so many death game stories going on at the same time, like the superhuman powered guy who always wanted to be a "player", and then the guy who was trapped in a dungeon for 10 years. Oddly, they're all Korean.