unsure if you wanted real spoilers or not but…
from what i’ve seen of spoilers so far it seems like this isn’t really an alternate universe! the “novel” that our mc keeps talking about was actually his first life but he doesn’t remember it like that (likely from trauma). the “real” world he references where he’s friends with iheon isn’t his “real life” like he thinks, and this world is real and his current life is actually his original world but he’s gone back in time or got reincarnated so he’s living through it again. and it seems like iheon might know this and is trying to treat him better this time??
Or maybe he does not know the future, his subconscious just warns him about it and planted fake memories into his mind - not many things from the future actually happened due to his cautiousness
But the book of his father is another thing, there is no way for him to just come up with something like that
It isnt really a spoiler warning, but I have a lil theory on what is going on - did his friend from the "og reality" just put him into this imaginary one to spend his life with him?
Or they theoretically got transported both with just a little delay on iheon's side.
Or these are just parallel universes where in one, they experience love together and in the other they miss the opportunity to be together due to huimin being ignorant to his friend's crush.
Idk really