I understand perfectly, what are y'all not understanding? Maybe I could help you out.
I think it’s cause the first prince interrupted the old man/tudi deity, the flowers thing (that I forgot abt with my shitty memory LOL). It said the flowers will have to go thru sum to become a greater person? I don’t remember much but the outline is the prince interrupted the mans process in become someone higher. When the flowers r in the process they emit this thing that makes them wanna bAng bAnG, and the prince did the bAng BAnG with the man so now he became a lowly tudi deity, so he tryna get revenge
From what I can tell, they were friends/lovers in the past. Something happened that caused the black dragon to imprison the white dragon. I don't know how or why, but the white dragon gave a part of itself to the black dragon so that he could live, which also caused him to have an incomplete soul. It seems like the older prince has memories of their past life and knows that a piece of the white dragon is missing.
I kinda feel sorry for him. He has no one except for Ao Ao, who doesn't even remember him.