Rolf Maroni is the leader of a gang called the Red Fists and brother of Sal Maroni, who is among the toughest gangsters in Gotham City. Rolf ended up dying in the end because of Harvey Dent in his Big Bad Harv persona which fueled Maroni's vendetta against the Dents.
Rolf allied with Fish Mooney and her gang to capture and eliminate Carmine Falcone. Rolf learned how Fish was once an high ranked member in the Falcone Crime Family and saw this as an opportunity to impress his father with Fish's knowledge. Rolf gave Fish a deal to kill Falcone in exchange for all her old territories. Fish took Falcone, Bruce Wayne, Hotwire, and Ethan Bennett prisoner to kill them all as part of the deal. Fish wanted an equal partnership, however Rolf wanted her to be his lieutenant. Fish ended up shooting Rolf in the head since Rolf kept sexually harassing her. However, Rolf was able to survive that gunshot wound.
Rolf got involved with his father's plans to revive Project Hades and saw Detective James Gordon as a threat. Rolf sent Arnold Flass and a group of corrupt cops to kidnap Lieutenant Colonel James Gordon Jr. who was at Arkham Asylum receiving treatment, however they all ended up being killed by Harvey Dent, who was using his Big Bad Harv persona to locate his father William since he needed him to make Dent Industries profitable.
A female scientist from China witnessed the project that Sal Maroni and Hugo were working on which prompted her to steal the information required to make everything work. Maroni ordered Rolf and the Red Fists to hunt down the scientist and retrieve the data. Rolf was seen getting into his car, however he got confronted by Harvey. Harvey interrogated Rolf on everything he needed to know to find William. Harvey flipped his lucky coin to decide whether to kill Rolf. The coin landed on its "good" side which made Harvey spare Rolf. Harvey flipped the coin again to decide the driver's life and it landed on that damaged side. Harvey secured himself in his seat belt and killed the driver which caused the car to crash, killing Rolf.