The Dawnbreaker

"With darkness black I choke the light,  no brightest day escapes my sight.  I turn the dawn into midnight,  beware my power... Dawnbreaker's might!"

- The Dawnbreaker’s oath

The Dawnbreaker 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 -32, while walking through a back alleyway, Thomas and Martha Wayne were shot and killed by an unknown gunman in front of their son Bruce Wayne. As young Bruce mourned over the loss of his parents, a Green Lantern Ring appeared and chose him to become a member of the Green Lantern Corps. Bruce decided to use the ring’s power to locate and kill the gunman who shot his parents, but the ring protested against this action and refused. However, Bruce's willpower and anguish overloaded the ring, which reprogrammed it to carry out the task. Bruce then began using his powers the fight crime with lethal force, but it did nothing to help the sorrow, anger and emptiness he felt inside himself.

Eventually, after murdering Jim Gordon for questioning his methods, Bruce was confronted by the Green Lantern Corps who attempted to arrest him, but he slaughtered them all using nightmarish constructs that reflected the void he felt within him. Afterwards, Bruce further empowered his corrupted ring by entering the Green Lantern Power Battery, then rejected his identity to adopt a new one inspired from the cave of bats beneath Wayne Manor, Batman. Soon Earth -32 began to break apart, and The Batman Who Laughs appeared to offer the newly christened Batman a place among the villainous Dark Knights as The Dawnbreaker.