Comments of chapter undefined of One Piece: Blood Unleashed [Revamped - in the synopsis]

Dark energy is a separated power system of Vlad, think of it like Haki. How does this power work? It circulates around the power of death energy, in a sense that all the death around him would send a small part of this death energy towards Vlad, accumulating until something bad would happen. You see Hades uses in chapter 6 to send Vlad to the OP world and explain a bit. It's his curse or blessing so to speak. He didn't ascend to heaven, but instead got stuck in the limbo/underworld. Yet, he will still have his haki, which will be in conflict with his dark energy.