Maybe he noticed he was feeling bad? And wanted to give him support. What I'm not sure of is whether or not the black haired guy knows what happened to Dan Zi. I think he doesn't...
Maybe he felt he needed to show that he was there, but backed off to respect his space. We don't see him in the last shot, but that doesn't mean he left the room. He could be on the other side waiting til his friend feels a bit better.
I see, so he backed off out of concern. I was confused of his backing off from the embrace or from the relationship. I hope he doesn't back off from the relationship! He has to help Dan Zi overcome his trauma, right? (๑•ㅂ•)و✧
Kyoutaro deserves an uke (๑•ㅂ•)و✧
I volunteer!!!! (●'◡'●)ノ
Dear, he'll make you very happy! (⌒▽⌒)