The so-called Qi Recovery Method is a kind of breathing technique for martial artists in the Mortal Realm. When one's Dantian Spirit Power is saturated, it is of no use, but after a battle where spirit power is depleted, it can effectively replenish the lost spirit power to its maximum.
From his self-developed fusion martial arts technique, Brother Xu must emit at least 4,500 points of spiritual power for a fusion skill, yet he can perform them consecutively. This could mean he has a secret method to conserve output of spiritual power. However, a more plausible possibility is that he possesses an unparalleled Qi Recovery Method.
This is the key factor that allows him to perform beyond his level. Without this method, his Sword Technique will be exhausted after being used twice. What use would that be?
