The white hair guy is the black hair guy as well. The very first chapter does not have the twin in it at all. You will see the twin but like much further into the story. So, the white hair guy is Hima, but like Hima further into future of the story. While the black hair guy is also Hima, but now you are visiting Hima past. You get to see Hima black hair eventually turn white as the story progresses. Like damn why is my hair turning grey on me. That sort of thing. Also, Than doesn't know that the white hair guy is Hima. He thinks Hima is dead.

this changed my life (i still don’t know wtf happened in ch 1)