Xiao Yang intended to cooperate with the Deer King. Since all the threatening enemies in the secret realm had been cleared out by him, and the source of the Great Dao power was left unguarded, he needed to find someone trustworthy to look after this spring.
The Deer King was the best candidate.
First of all, there was the relationship between the Seventh Sister and Tianqing, and Xiao Yang had saved his life before. If he didn't choose the Deer King, was he supposed to choose the Tree King, with whom he had no relationship at all?
Chapter 644