Apart from the Heaven-Devouring Hou and the Jade Devouring Sky Python, there were other cultivators who could defeat Wu Ling and Ling Tian in turn, forcing Chi Xue and Po Tian to stay out of the fight. Those would be other peak fifth-stage Quasi-Saints or sixth-stage Quasi-Saints. As long as they could defeat Wu Ling and then Ling Tian, Chi Xue and Po Tian wouldn't need to fight, and could stay out of it.
Chi Xue knew, however, that getting sixth-stage Quasi-Saints to make a move was unrealistic. Experts of that level had to hide their strength. If they revealed their true power, they might suddenly die or go missing. Not one of them would dare act rashly, especially without confidence that they could capture Ling Tian.
That made sense. Sixth-stage Quasi-Saints wouldn't target Ling Tian just to damage Fengyun Pavilion's reputation. They wanted the Phoenix Soul Fruit, or at the very least, the Nine Reversals Heavenly Technique. The former would let them be reborn through nirvana, while the latter could make their disciples powerful enough to take the final step—and then bring them out of this universe. That would free them from the Lord of the Universe's restraints.
In the past, sixth-stage Quasi-Saints might have been confident they could capture Ling Tian without revealing their true strength, then trade him for the Phoenix Soul Fruit or the Nine Reversals Heavenly Technique. But after seeing Ling Tian's challenge match against Gao Feng and the others, they had lost that confidence. Even if they believed they could defeat him, they weren't sure they could capture him.
As mentioned before, defeating or killing Ling Tian meant nothing to them. They would only risk sudden death or disappearance, and at the very least, they would offend Fengyun Pavilion. Experts of their caliber wouldn't