Bruce Wayne (Earth-X)

"This city is filled with wretched scum like you, polluting the streets and corrupting the citizens with your filth. The city needs a hero to clean up the mess, and an executioner to clean up the crime."

- Batman to a criminal

Origins
As a young child, Bruce Wayne watched his parents, Thomas and Martha Wayne, get murdered. While walking home from the opera one night, they were held at gunpoint. The criminal, later revealed as Joe Chill, wanted Martha's pearl necklace but Thomas refused to let him take it. They were both shot and killed and Bruce was left in the alley all alone. Alfred Pennyworth, their butler, finally came looking for them a few hours later and found Bruce traumatized in the alley. He took the young boy home and comforted him. Alfred raised Bruce from that point on.

Training
At a very young age, Bruce already knew he wanted to stop the crime in Gotham City and avenge his parents. He started training on his 9th birthday. By the time he was 14, he traveled across the globe learning different kinds of martail arts until he came across one group in Bhutan. While there, he met Ra's al Ghul who brought him into the League of Assassins, a secret organization with the world's greatest knowledge of martial arts.

He spent a few years in the organization until one day, when he was nineteen, he discovered their evil terrorist ways. Bruce refused to kill a politician they had kidnapped for his final test. This made Bruce an outcast of the organization and they tried to kill him but Bruce escaped. He eventually made it back to Gotham City.