History
Fixit is the main gadget-man in Vanity City.
When Death-Doll needed to find Aztek, Fixit pretended to be mugged by her thugs. He also provided her with the weapons she would later use in her battle with Aztek. Naturally, once she had the advanced weapons Death-Doll only gave Fixit about $20.
When the Joker visited Vanity, Fixit also provided him with the mind-controlling dancing crickets he had requested. When Batman came to investigate, he let Fixit be.