Carl Grissom

Carl Grissom was the most powerful crime lord in Gotham City prior to Batman's emergence.

Biography
Carl Grissom was the most powerful crime lord in Gotham City, with some or even most of the GCPD on his payroll, including Lieutenant Eckhardt. When the recently-elected District Attorney Harvey Dent began to make connections between Grissom and Axis Chemicals, Grissom panicked, and knew that the evidence that was stored at the plant was enough to have him either sent to prison for life or sentenced to the death penalty.

Grissom also found out somewhere along the line that his mistress, Alicia Hunt, had an affair with his second-in-command, Jack Napier. (It's implied that he may have found out from crooked GCPD Lieutenant Eckhardt due to the latter's asking under his breath "Where [has Jack Napier] been spending [his] nights?") In revenge, Grissom sent Napier and his men to Axis Chemicals to seize the evidence before Dent could. At the same time, Grissom called Eckhardt and ordered him to lead a team of police officers to kill Napier. The plan failed when Commissioner Gordon intervened to take Napier in alive as a potential witness. Eckhardt then attempted to escape, but was shot in the chest and killed by a vengeful Napier. Napier was then confronted by Batman, but fell into a vat of chemicals, and left Grissom to believe that he was dead, much to his delight.

The next night, after a shower, Grissom had a visit from Napier, who survived the ordeal and wanted revenge. Grissom feigned relief, but Napier scoffed him, and played wise to his moves. Grissom also subtly attempted to reach for his gun, although Napier told him not to even bother reaching for it. Grissom then pleaded for his life by offering to cut a new deal with Napier, but Napier refused and instead revealed his new identity: The Joker, with white skin, green hair, and a widened and permanent red grin. At that point, Joker shot Grissom to death and took over his criminal empire.

Legacy
After Grissom died, Joker tried to manipulate the mob kingpins into believing that Grissom was in hiding and that Grissom left him in charge. Rotelli was suspicious of the Joker because of his bizarre grin and did not want to take orders from him. As a result, Joker electrocuted Rotelli to death with his joy buzzer and then, the following day, he assassinated Vinnie Ricorso on steps of City Hall when Ricorso tried to use law and manipulation against the Joker by filing a false affidavit that stated that Grissom had instead handed Ricorso all of his operations. As for Alicia, she would fall to her death later on, which was implied to be either suicide from the macabre lifestyle that Joker introduced her to, or murder (as Joker now had affections for the photojournalist Vicki Vale instead of her). Grissom's death would be avenged when the Joker fell to his death from a helicopter while trying to escape from Batman.

Despite his death, Grissom's indirect creation of the Joker would pave the way for numerous criminals who were similar to the Joker such as the Penguin, Catwoman, the Riddler, Two-Face, Mr. Freeze, Poison Ivy and Bane, who were all inspired by the actions of the Joker.

A department store owner named Max Shreck, who was quite similar to Grissom, would try to take advantage of the new era by working with the Penguin to terrorize the city in a bid for Penguin to become mayor so that Shreck's power plant could be approved. Similar to Grissom, Shreck would be responsible for the creation of Catwoman, who was almost as unstable as the Joker, and then meet his death at the hands of Catwoman in cold blood similar to how Grissom died at the hands of the Joker.

Following Shreck's death, the final remaining mob boss left in Gotham was Sal Moroni, who accidentally created Two-Face in an attempt to kill him in court under the belief that he was secretly a murderer targeting the remnants of the criminal underworld. Moroni was presumably convicted of his actions, as they were witnessed inside a courtroom full of law officials.