The Merciless

The Merciless is a villainous version of Batman from the DC Comics universe. He is a member of the Dark Knights, a group of vigilantes from the Dark Mutiverse whose goal is to assist the deity Barbatos plunge the central DC Multiverse into darkness.

Origin
On Earth -12, the God of War Ares managed to create a helmet that amplified his powers a hundredfold. After learning of this, Batman and Wonder Woman vowed to slay the god and destroy his helmet. The pair got embroiled in a two year long war against Ares’ forces before finally confronting the deity in combat, during which Wonder Woman was seemingly killed. Heartbroken over losing the woman he loved, Batman swore Ares would pay then used the God of War’s helmet to kill him, although it’s power corrupted Batman's mind in the process. Afterwards, Batman found that Wonder Woman was still alive and had just be stunned by Ares, but when she tried to remove the helmet from him, Batman chose to kill her rather than give up it's power.

The empowered Batman then dropped his moral code and went on a killing spree; murdering various criminals and later heroes who tried to stop him. Eventually Batman’s rampage took him to Olympus as Earth -12 began to collapse, and was given the opportunity by The Batman Who Laughs to take part in “the greatest war the cosmos has ever seen”; a war of survival. Wanting to prove that his new philosophy is the correct one and having nothing left to loose, Batman took up his counterpart’s offer and joined the Dark Knights as The Merciless.