Without the power of the Enochian Cradle, the Realm's Butcher Onslaught was the single most powerful technique in his arsenal, but its power did not come because of the amount of energy it could siphon from his body—which was infinite due to the fact that this technique fed on his rage, and his soul, taking from it a permanent toll—it was because it was a pure killing tool.
There was no way to wield it so it would injure or be harmless, and the only way to survive it was to be strong enough, because anything that it cuts would die.
This technique was meant to kill an enemy that was supposed to be impossible to kill, and the best scenario for this attack was to send it at a far enough distance from yourself because its power was indiscriminate, and there was nothing keeping the wielder of this power safe from its bite.
