Responses
Because, like Infinityandbeyond said, every time he fails and dies, everything resets and goes back to the beginning. They won’t warn anyone because they don’t know the cycle is being repeated over and over again/no memories whatsoever. That is Sisyphus’ (Guwon) punishment. I like to think of it as “Groundhog Day” or “The Good Place”.

So if y’all know the story of Sisyphus, it’s basically just about eternal struggle and never being able to complete your task. Sisyphus is doomed to push a boulder up a hill, never reaching the top because it rolls back down again and again, for an eternity.
In that same way, remember there was a boulder in the early chapters? Except what I think happens here is Guwon, some sort of non-human entity, is tasked something impossible. Instead of the boulder, his task is to establish a perfect town with perfect people working together in harmony, away from the apocalypse outside.
Except he fails. Every time.
And once he dies, everything resets again with no previous memories.
So in summary, it’s like a trial over and over again. Idk what he is or what he did to get punished with sisyphus’s fate, but I think this time things will change and they will be able to break the cycle with Teach’s help.
Just my theory!