  Chuckie Sol is a mob boss and an adversary of Batman in Mask of the Phantasm. He was an enforcer of Sal Valestra and worked with a hitman who would later become the Joker.
History
Before Batman
Chuckie at some point became a mob enforcer for Sal Valestra and they ruled Gotham before Batman showed up in Gotham. A man named Carl Beaumont came to them for money and they did gave him money. However,
Chuckie Sol when he was working for Sal Valestra.
Beaumont didn't pay them back. One night, they visited Carl's house and made threats to pay them back. Carl promised Sal that he'll pay them back in 24 hours which Chuckie agrees on. But, Carl used the time to escape to the Meditterenaean and managed to pay them back. Arthur Reeves, Carl's assistant was desperate for cash so he gave the mob the location of Beaumont and told them of his embezzled fortune. The mob sent the hitman who would later become the Joker to kill Beaumont.
Final Days
Years after the event, Chuckie managed to make his crime empire and make counterfeit money