It's his real one and it's confusing rn but in the end of the manhwa it's revealed why the game was even created in the first place. The reason why the game was created is why she's here in the game too
Babes the manga is not completed, you’re talking about drama or novel or whatever this manga is based on.
And it’s pretty much different than the direction where this manga is unraveling to.
I'm sure the whole reason why he's in the novel/game to make yeowoon happy is for the same reason in the drama because it all makes sense that the novel/game exists to make mc happy unless the manhwa really does go in a different direction
so is that his real grandma or the fictional grandma in the novel. Because why is he so attached to a fictional grandmother and if she is real why was she written into the book?