Bruce Wayne (Earth-31)

"'That bastard killed my parents, Kate! He shot them in cold blood, and then ran like a coward!! When I find him...I'll make him wish he killed me in that alley. Then I'll kill him!' - Bruce to Kate Kane (Earth-3)"

Bruce Wayne is human vigilante from Earth-31 known as Batman.

Biography
Bruce is first seen walking home with his parents, Thomas and Martha Wayne, after going to a movie. Suddenly, a masked man holds the family at gunpoint before shooting Bruce's mother and father for seemingly no reason. The man then takes Thomas' wallet and runs off, leaving young Bruce distraught as he screams over the bodies of his dead parents, wrought with grief.

As Bruce mourns his dead parents, he meets Jim Gordon, who vows to find his parents' killer, no matter what it takes. Bruce nods and tells Gordon that he hopes this man suffers for what he did. He is then taken home by his butler Alfred Pennyworth.

At some point after that, he meets Selina Kyle.

Bruce visits Crime Alley, where his parents were killed. As he mourns them, some thugs walk up to him and make fun of his dead parents, enraging Bruce enough to call them "mongoloids with no capacity for thought". They almost attack Bruce, but the goons are beaten up by Hulk.