"Battle spirit…" Charcoal became serious from its initial apathy towards the Herculean Ape. There was a detailed explanation of human battle spirit in the dragonkin's inherited memory. The battle spirit was extracted from the monster and put into the human's spirit in a unique way. The battle spirit could be summoned to join battles by inserting Life Power.
The battle spirit on top of Lu Feng looked like it was formed completely using Life Power but that was not the truth. The Life Power was used to activate the battle spirit while the forming of the battle spirit came from the battle spirit itself. If Lu Feng were to activate the battle spirit with his Life Power, a single attack would drain his Life Power completely.