In order to reach higher levels of cultivation, one need to increase the strength of one's Blood Energy, otherwise it will be unable to support increasing demands of the Physique, Life Wheel and Fate Palace; thus, there is a need for the Blood Energy to be purified into the Longevity Blood by using the Life Wheel Merit Law.
Blood Energy can increase the might of attacks. It is also used to wield and control the Immortal Emperor Life Treasures. The stronger one's Blood Energy, the more power one can extract from the Treasure. Normal cultivators, with average amount of the Blood Energy, can use only 10 to 20 % of the Immortal Emperor Life Treasure's power, while Li Qiye, with his abundant amount of Energy was able to use 60%.