From Shoryuken Wiki, Marvel vs. Capcom 3 Strategy and More!
Black Dahlia, the Medici Mafia's top ranked assassin, has more than enough experience to make up for her age. She killed the entire Fishbone Gang, cut Ms. Fortune to pieces, and put countless other hits under her belt for Vitale. With the younger Cerebella becoming the boss's new favorite, Black Dahlia may be jealous enough to peruse the Skull Heart for her own selfish purposes as a DLC character.
Black Dahlia patiently waits at the Medici Tower stage until Vitale gives her new targets. Although infamous across the Canopy Kingdom, there are no known photographs of Dahlia's true face; she's far too arrogant to show her scars. With no fear of getting caught, she wears her preferred murder weapon as a prosthetic arm and uses it as often as possible to launch a variety of high-caliber round, tear gas canisters, and grenades. She would gun down Noel, Hol Horse, and Chris Redfield just to make a point. Black Dahlia also pioneered the Medici assassin art of fighting with concealed bladed weapons, so there's no telling what other implements she has concealed in that silky dress.