Responses
The "real world" is the book world. The book came to ml in the fake world (it's not explained why) and that's how he saw mc's perspective of their lives. The book might have been manifested by Mc in the fake world to get ml to understand him better, since they were so bad at communicating in their first lives.

This was a rollercoaster but there's something maybe I didn't understand or maybe that was never mentioned. Is there like a real world? From what I understood they are from a book so where does the book come from or is like a metaphor or something? That's the only thing I didn't get.