Why is aaron so hung up on him again? 😭 I still can’t fully grasp their relationship ...

Same the only thing I can think of is the whole sleep thing but even then i don’t really know

Aaron was obsessed with Yujin's voice and music since it was the only thing can helps him sleep after going through traumatic accident (getting shoot (tried to) by a madman Yujin's dad). They meet and Aaron starts to think Yujin is something to hunt, then to tame, then he's completely obsessed. He's gone bad.