My brother (Yun Yu) whom I haven't seen for several years after being sent to the frontier
Yun Heng has already found a reason why his brother has never replied to a letter.
After several years of separation, Yun Yu was made a prince almost as soon as he arrived at Yun Heng in the border area. Once, all of Yun Heng's letters were as if they were lost in the ocean. Nothing from his staff or friends could compare to Yun Yu's thoughtful courtesy and indifferent expression when he returned, which made his heart tremble.
Yun Heng poisoned Yun Yu, the poison of the ghost clan.
In order to gain Yun Heng's support, as the god Yun Yu believed in, the man deceived him and told him that he would harm others if he did not rely on the pure yang body to maintain his body temperature.
Later, Yun Heng felt that he was really dragging the prince down and ran away. On the way, he met a man who told him the truth. He didn't believe it at first, but after a few test words, the prince thought he knew, so he ran away and told him everything.
Finally, the prince imprisoned his brother in a palace built above the clouds.
Conception:.