
Idek, I think the og iheon doesn't really like the ml... To me he seems to create his diary out of external factors with underlying meaning... I mean he accused the ml of being a manipulator, considering his mother was also used by what kind of people (I think this is what it means by history repeats itself?) he's trying to decipher the ml? Anyways this is just a weird hypothesis, the og iheon is not on his prime like her mom before getting manipulated.
Edit: Personally me, I find the plot weird... It feels like something is missing and I quite don't find it fond to read. Though I'm gonna see if this will turn out great.

Does anyone know it's novel?

Yes, it’s a novel.
Here’s the link boo
https://www.novelupdates.com/series/gatekeeper-of-the-boundless-world/
It's so confusing, but one thing I know is that I like this... The art style is very giving. The mc's is just pure gorgeous that idek