Leviathan/characters/archive/B-621

B-621 is a supervillain and the archenemy of Batman. He was first introduced in Batman #1 (Spring 1940) and has remained consistently popular. B-621 is a master criminal with a clown-like appearance. Initially portrayed as a violent sociopath who murders people for his own amusement, B-621 later in the 1940s began to be written as a goofy trickster-thief. That characterization continued through the late-1950s and 1960s before the character became again depicted as a vicious, calculating, psychopathic killer. B-621 has been responsible for numerous tragedies in Batman's life, including the paralysis of Barbara Gordon (Batgirl/Oracle) and the murders of Jason Todd (the second Robin) and Jim Gordon's second wife Sarah Essen.

Okay, seriously though

Formerly known as Badstar Marian Strunner, his life was taken away by his own brother, Homestrong Twinkletoes Strunner. Shortly after his death, Homestrong realized the horrible mistake he had made and decided to spend the rest of his life dedicated to reviving his brother through science and machinery. After three long years, Homestrong was finally able to replace 99.99% of his brother's body with robotic parts and various weaponry, such as lasers, rocket boosters, bladesaws, anything to prevent another death. He named this creation B-621. While memories of his past life were long gone, the original Badstar's personality remained, though his sibling rivalry with his brother did not continue and they had a loving relationship for many years to come. Shortly before Homestrong died of old age, he deactivated B-621, setting him to reboot in a safer time. ...It didn't really help, as Homestrong's lab was looted 2 weeks after his death and B-621 was sold to a traveling salesman by the name of "Trashboat Travis". As years went on and the world moved further and further into a new age, B-621's ultimate fate was to end up in a junkyard, where Captain Seth bought him for 2 bucks and a gummy worm. He now faithfully serves the captain as his ZAAAAAANY ROBOT COMPANION!