Not long after Jing Ming left, Lu Yuan wrote a letter to persuade Xu Wan'er to go to the Upper Realm.
In fact, even if Jing Ming hadn't asked him to do so, Lu Yuan would have done it.
After all, the reason why he stayed in the Lower Realm was because he had the skill interface. Even if the spiritual energy in the Lower Realm was not as dense as in the Upper Realm, its density did not have much of an impact on Lu Yuan.
On the contrary, Lu Yuan was most interested in skill proficiency.
After all, the improvement of his skill was equivalent to the improvement of his cultivation.
As long as he had sufficient cultivation, there were simply too many ways for him to increase his spiritual energy.
Moreover, Lu Yuan himself already had several methods to do so.
This included, but was not limited to, setting up arrays that could speed up the absorption of spiritual energy or refining pills that could help him do the same.