
I think he may have died in the collapsing building along with the sister and the ML or the ml took his life after her died and met in this “reality “ with partial memories from the previous life/reality. The ml said “I thought for sure you’d have a little sister “ maybe that’s why he didn’t behave as “expected “ and he appeared earlier than the mc expected.

I also think that's what happened! And idk but I have a feeling the more time they spend togather the more memories he'll regained from his pass life. I also feel like the Mc didn't die from the ceiling that fell in that one memory we saw, I feel like maybe his hyung probably did while saving him which probably have led him into despair and he either ended up dying later or taking his own life (anyways i'm so excited to find out what really happened!!)
So the ML is his hyung from his original life, but he doesn't remember his face because he doesn't remember stuff. we get a clear glimpse of their piercings at a certain flashback, so that's obvious. the real question is how things are going. did he die in his original life and came back to life in this one, does he simply remember a past life or alternate life? and what about the ML? does he belong to this world or is he also from another world? this is where it gets interesting to find out how things will play. Also, I like how the MC doesnt simply settle in the BL world, not exactly, he wants to get back to his usual self and is stubborn about it. but the fact that he becomes sick whenever he fights the reality makes me think that this is simply the only reality left for him, whatever the reason.
btw I really love the ML s dimples, they are super cute.