Ok basically! [heavy spoilers]
In a previous chapter Bihwan was told by the guy with piss colored eyes (his older brother) that Minchan is a vessel for Bihwan’s man. He is a fragment of his soul, I think, and B’s older brother is wanting to make it whole again. Biwan wants to tell Minchan, but his brother kind of threatens him/scares him against telling Minchan the truth to avoid him having a mental breakdown.
Bihwan was told during this that Minchan would essentially no longer be himself, it would be like a soul consuming another. And it’s rlly interesting bc you can see he’s both yearning for Seo back but cannot just easily let Minchan disappear
So cut forward, we’re in the fucking shit of it all now. Grandmama is just airing everything out for Minchan, and literally—Minchan has had his entire reality shattered. He’s hearing that his family (both his grandmother and ??? Idk what even piss eyes is to him) are seeing him as an empty body essentially. And on top of that, the guy he’s been with KNEW and lied about it (yes not to hurt him, and yes, Bihwan loves Minchan buuut) to avoid having to choose.
Piss eyes used powers on Bihwan, to force him to make Minchan drink a vial that causes the soul unification to “begin the end” of Minchan.
But after this happens, Minchan as Seo (I’m sorry I do not remember how to spell his name) is forced into a dream in the place where Bihwan was trapped as a kid. He is where all comes back to, so nothing in this place is moving on a reasonable time scale.
Seo is offered the ability to escape that place, or save someone from that place
Seo see’s Bihwan as a kid and decides to save baby Bihwan (▰˘◡˘▰)
and then Minchan wakes up and tells adult Biwan he had a dream about Seo and Biwan cries.
preferably midway through the arc... its been a good while since i reread this and i forgot what happened after the AU. i knew from the comments that there’s a time travel/time loop shenanigan going on but AHHH please help me out（/TДT)/