As Al Capone's righthand man Frank Nitti in Brian De Palma's The Untouchables, character actor Billy Drago makes for a very formidable enforcer. He's the Chicago crime outfit's deadliest gun, the enforcer that Capone tasks with unloading multiple Tommy gun bullets into elder officer Jim Malone (Sean Connery) in one of the movie's better sequences, as well as killing a police-protected snitch in a precinct. And Drago—a slithery, skeletal-looking presence who's able to induce fear more through creepiness than physical intimidation—owns the role.
Interestingly, however, Drago's version of Nitti isn't all that much like the real version. Using some creative license, screenwriter David Mamet changed Nitti's story quite a bit for the film's benefit. In reality, Nitti handled Capone's financial pursuits, not his body-dropping assignments. For those tasks, Capone was more likely to call upon Fred Burke or Jack McGurn.
And when Drago's Nitti dies from Ness pushing him off of a rooftop, that's just Mamet providing a satisfying, good-conquers-evil conclusion—really, Nitti ran Capone's operation for six years after the latter's death, before committing suicide in 1943 to avoid a potential jail sentence.