"Xiaoshuang, whatever I have to teach you lies in the sword moves I have demonstrated over the past several months. How much insight you gain is up to you."
Yi Yun had used the period of time to impart all of Azure Yang Lord's heritage, as well as his own insights in it, to the Clarity Pool Sword Sect to the best of his ability.
Of course, Yi Yun's Chaos and Major Destruction Dao and Space-Time laws were unique to him, especially the former. Even if Yi Yun wanted to teach them, it would be impossible for them to learn it.
After Yi Yun destroyed the Seven Star Dao Palace, he stayed in the Clarity Pool Sword Sect for ten months. Over those ten months, he read through all the notes left behind by the divine alchemist and memorized them.
He found three potential methods to save Ling Xie'er. And in all three methods, the Red Cauldron Sect's Soul Returning Root was a crucial ingredient.