If you're saying the Frank Costello character was taken from Whitey Bulger, I'd agree as Bulger and Costello share many of the same traits.
The character Frank Costello was largely based on James "Whitey" Bulger, a real life Irish-American mobster in Boston who was secretly an FBI informant for over three decades. The revelation that the FBI had long protected Bulger and his gang from prosecution caused a major scandal in Boston law enforcement. Bulger was believed to have been seen coming out of a theater showing the film in San Diego in November 2006.[3][4] Matt Damon's character is based on John Connolly, the FBI agent who tipped off Bulger for years, allowing him to evade arrest. In real life, Bulger went into hiding and is still presumed to be at large, currently occupying a spot on the FBI Ten Most Wanted Fugitives list; Connolly is currently imprisoned for his role in Bulger's criminal activities.[5] Billy's undercover role as a former State trooper who joins the Irish mob parallels the story of Richard Marinick, a former State trooper who later joined Whitey Bulger's crime syndicate. Billy also lives in Somerville, where Bulger's Winter Hill Gang began. Thomas Duffy, the film's technical advisor (he also plays the Governor at the State Police Academy graduation ceremony), is a former MSP major who was assigned to investigate the Irish mob upon making detective.Sorry, I've gone way off topic. Let me come back to the topic by saying I'd also agree that Frank, Whitey and Teddy share lots of traits.
“I’d also agree that Frank, Whitey and Teddy share lots of traits”
Amen! There were/are filthy scumbags.
One thing always sticks out about ‘The Departed’: An Irishman named Frank Costello? Doesn’t sound too Irish to me. There was a real Frank Costello that was a member of the the Luciano/Genovese crime family.