Yang Zhen was initially interested in the Heavenly Star Stele, and the nonsense origin of his "teacher" was devised just so that the Yaochi Holy Land could regard him more highly.
As for Yang Zhen's true intentions, it wasn't to comprehend any Star Power of the Heavenly Star Stele, but rather to have a status that would allow Yaochi Holy Land to negotiate with him respectfully. When the time came to borrow the Seven Yin and Seven Yang Land, he would have something to bargain with.
After hearing what the Third Saintess Wang Yuxuan had to say, a strange expression appeared on Yang Zhen's face. He asked, "Help you with this task, does it require two people to achieve?"
Wang Yuxuan's face betrayed an unnatural expression. She nodded and responded, "Yes, because the Heavenly Star Stele is... a secret treasure born of Yin and Yang harmony, created by the heavens and earth, thus it cannot be comprehended or activated by just one person."