
The uke saved the seme and shares a traumatic event (unlocking their malice AKA those hands and evil thoughts from their own inner selves).
As time went, the uke forgot his childhood to fit in the society, while the seme was doing everything while having the uke in mind (writing the book and coming back to Korea).
Overall, the seme patiently wait for the uke to remember the past they shared (he's violent to everyone else tho bahaha).
Hoped it helped, and sorry if I wrote too much.

Lol no they aren't. Well spoiler butbthey are physical manifestations of Seme and ukes malicious intent. They only care for each other and want to be alone together. So they basically kill anyone who comes between them. And since seme remembers most of it. He uses this to murder people who are separating him from uke.
I just want someone to summarize the whole thing. SOMEONE PLS