The soul-burying emperor at the beginning of the domain is a fan of Yue Tianji.
I just watched episodes 1-6, a clip of YY's future development.
Background setting: Yue Tianji betrayed the Soul Burial Emperor midway, but after various twists and turns, he settled his suspicions.
The final battle is when Soul Burial Emperor and Ji Wushuang join forces to fight against the control of Universe Tianzun.