Is the poster asking before he went down the mountain or after he went down the mountain?
If he followed Han Lingsha down the mountain, then it is very simple. His father (Yun Tianqing) and mother (Suyu) escaped down the mountain during the battle between Qionghua and the demon world nineteen years ago. He lived in seclusion on Qingluan Peak. Yun Tianhe's parents died early, so he, who was not familiar with the world, never came down the mountain. After reading the plot carefully, it should be that Yun Tianqing wanted Yun Tianhe to ignore the world and live a peaceful life. This kind of life until It was broken when Han Lingsha appeared
If you ask why they wanted to live in seclusion at Qingluan Peak at the end of the play, then seclusion was actually Han Lingsha's wish. When Qionghua encountered a sudden change, Han Lingsha knew that she was the host body of Wangshu sword, and Xuanxiao was the host body of Xihe sword. Xuanxiao and Suyao planned to use these two swords to make sword pillars and ascend to immortality, but Wangshu sword was in Suyao Hands, excessive use made Han Lingsha weak, and Han Lingsha would die when the sword pillar was finally made. They returned to Qingluan Peak to find a way to save Han Lingsha's life. At this time, Han Lingsha felt that she had been Yuntianhe's life in the mountains is peaceful and satisfying, and he longs for it. The four people who survived the disaster, Murong Ziying became the new leader of the Qionghua Sect, Liu Mengli inherited the Illusory Underworld, and Yun Tianhe and Han Lingsha got married as a matter of course and lived in seclusion. The final animation of the game was played a hundred years later. All the fairy sword fans know, no more nonsense~