I think it was literally just because Hyo-un didn’t like him and Taehyuk wanted to respect his feelings on it (that’s what’s implied anyway when he says his dragon will be jealous etc). It did feel like a lacklustre resolution to their relationship, I’m guessing the author just wanted to wrap it up quickly
Well he did indirectly cause his death in his previous life (which lead to Hyo-un - the one he loves - living a life of immense suffering for centuries). That would be hard to get over for a lot of people even if it was in the past. It's sad for older bro but to me there was nothing strange about it at all and the resolution was handled just fine. Time can't fix everything and there are certain actions that can't be undone.
Ughhh such a good story!! Can someone explain to me why he cut ties with his brother in modern time? Like I know his past self was a villain but this version of his brother was just that. There didn’t seem to be any negative connotations in their modern life. I know the brother kept all his memories which means he knew he was bad and all that but thats kind of out of his control. He was reborn countless times and it wasn’t until 300yrs later that he got a second chance at redemption and he was just good to Taeyuk and they lived normally so why cut ties??? Someone please tell me i didn’t miss something important.