"By the time Yang Chun kills Duan Ling Tian and avenges his brother, I'll ask him for a favor — recommend me as the disciple of that Martial Emperor behind him!" Yun Gang's eyes glimmered with brilliance as he wore a confident expression. "He'd owe me a favor, so it'll hard for him to reject my request…"
The disciple of a Martial Emperor! This was the true intention of Yun Gang.
Long before after he had witnessed Yang Hong being killed by Duan Ling Tian, this idea had popped up in his mind.
He thought of using Yang Hong's death and Duan Ling Tian so that Yang Chun would not be able to reject this request of his.
As for the part where he asked Duan Ling Tian to become the Sect Leader of the Yin Yang Sect later, that was just a small part of his plan so that Duan Ling Tian would remain with the sect.
If he had not made such a request, Duan Ling Tian would have never remained. By that time, it would be useless even if he went to look for Yang Chun.