1.0 Timeline: Huimin is suffering and sad so he draws stuff he wishes would happen like having a family, no ABO, different hobbies, etc. *everyone dies*
(1.5 AU) Alternate Universe Timeline: A reality where MC's drawings are "real" (They're basically in some sort of purgatory) Iheon shows up and wishes to go back to the 1st timeline when this reality inevitably comes to an end to try and keep them together forever.
2.0 Timeline (Also Current Timeline): Huimin starts out with only the memories he had of the AU timeline and Iheon only has memories of the 1.0 reality. As time goes on MC remembers more stuff from the first timeline, and Iheon gets all his memories from the AU timeline after they fucked cause it opened up his 3rd eye (jkjk it's just the moment the 1st timeline {1.0} and 2nd {2.0} timeline truly diverge)

Danggg I never expected that plot twist...Hats off to the author