James summoned all the Demonic Energy in his body to heal his injuries.

Since he possessed the Demonic Body, the stronger his physical body became, the more Demonic Energy would materialize from within it. Though the Demonic Energy inside his body was much more immense than before, he had been struck repeatedly by the lightning tribulation. Demonic Energy was being depleted to heal his physical body. Currently, not much Demonic Energy remained inside him. In fact, his remaining Demonic Energy w