The two Dao Fruits, Taiyin and Taiyang, complemented each other. Naturally, their effects were maximized when they were together.
A True Monarch's Grotto Heaven also needs a Dao Fruit to advance their Daoist Cultivation, and the interdependence of Yin and Yang is crucial for True Monarchs in the Golden Core Realm.
Thus, Dao Fruits with Taiyin and Taiyang attributes were naturally exceptional treasures.
Xu Yunfan's true goal was to leverage his Profound Capital Eight Sceneries Celestial Refining Creation Cloud Scripture, now on the verge of Perfection. By combining it with the unique Magical Power of his Divine Sky Nine Heavens Profound Vault Undying True Scripture, he would refine a Magical Treasure. This treasure would serve as a specialized container, designed for one purpose: to temporarily house the core of the Taiyin Profound Mirror Dao Fruit.
