 In the anime an electrical generator provides him with limitless power, effectively making him invulnerable.In his initial fight in the anime he easily beat Dark Phantom and Yeti Blizzard, then when he turned on Mega Man under Vega's orders not even Berserk Sword's power (with which Mega Man seemed invincible in all his earlier battles) could stop him.The only downside to this was that his range was greatly limited, and he would be rendered vulnerable if the generator was damaged or destroyed, this likely being the reason Vega had Mega Man collect the OOparts, since Hollow was limited to where the generator was, but when given the OOparts he took from Dark Phantom and Yeti Blizzard he overcame this weakness.