Umberto Maroni is the son of Salvatore Maroni. After his father's death he and his brother, Pino Maroni, run the Maroni crime family in Gotham City.
His first appearance is in Batman: Dark Victory #1, where Batman finds Gotham City caught in the middle of a battle, between what's left of the Falcone and Maroni mobs, and freakish villains such as the The Joker, Mr. Freeze and Catwoman. Meanwhile, the serial killer named Holiday seems to have returned to a life of crime. Batman investigates the death of Clancy O'Hara's, the chief of the G.C.P.D., one of the few uncorruptible.
In Batman: Dark Victory #3, the Scarecrow has his way: a nasty little toy called "The Fear Doll." New nightmares are unleashed on Batman as he faces one of his most dangerous foes. Umberto Maroni, like his brother, is a suspect, as the victims seem to be cops who came into contact with the mafias. Meanwhile, the third victim is found. Arnold Flass was one of the more corrupt officers on the force, only to get caught in criminal activity, fired and prosecuted for affiliating with the mob.
In Batman: Dark Victory #4, Batman and the GCPD have noticed on key piece. They are wondering where is Two-Face. Taking matters in his own hands, Batman looks for Dent, so he goes to Solomon Grundy, who lives under the sewers, where Two-Face sets up camp. It goes bad, when they fight and Grundy loses. Meanwhile, the Maroni's and Falcone's are their New Year's parties, while the 4th victim comes up. Former head of the Special Weapons Unit of the GCPD, Branden was hanged in a meat locker on New Year's Day.
In Batman: Dark Victory #5, secrets are revealed and decisions are made that will affect Batman, Catwoman, Jim Gordon and Janice Porter for the rest of their lives. Janice Porter knows where Two-Face is, because she is in love with him and been having a sexual relationship. Batman faces problems, as he goes to find the Hangman, while his time with Selina Kyle waits. Jim Gordon has a list of suspects, such as Two-Face, the mob, or maybe other villains like the Riddler. However, all of this is interrupted by the 5th victim. Pratt worked for the SPW Unit up until he was killed on Valentine's Day.
In Batman: Dark Victory #8, Bruce Wayne attends a night at the circus and a certain 10-year-old boy enters his life. Yet, Joker has just escaped Arkham and plans to blow up the whole city. Luckily, Batman and Robin fight and beat the Joker. Worried, the Maroni's are armed as they see if Commissioner Gordon can be found, they can too. This fact is also found both the police and the Falcone's. Yet, protecting Gordon, the 8th victim is found. Gustavson was the bodyguard of Gordon and found by Gordon hanging over his car in the GCPD underground parking lot.
In Batman: Dark Victory #11, the number of clues, and the body count, continue to climb during the heat of the summer. Batman confronts Poison Ivy as she makes her move. She plans to get back on those who screwed her during the Holiday breakout. Meanwhile, Dick Grayson gets closer to finding his parents' killer. Commissioner finds the recent victim and catches a break of the Hangman case. A newcomer to the G.C.P.D., Wilcox seemed to be a dilligent and articulate police officer. During the trial, on Labor Day, she headed up to the courthouse via elevator, only to get hung by the Hangman. Her walkie-talkie left a brief recording of her final moments that led Gordon to learning the true identity of the killer. Both Maroni brothers are resting and waiting what's going to happen next.
In Batman: Dark Victory #13, it's Columbus Day, and Two-Face, Freeze, Ivy, and the Joker found themselves in the Batcave. Pino and Umberto Maroni were in their own restaurant, as Two-Face meets them. Unknown, they were working together to face anyone who opposed any of them. Yet, to clean up loose ties, he shot both of them at two in the morning with two shots each to the chest, killing them in their own restaurant.