The proprietor of The Gem Saloon was six months ahead of everyone else in Deadwood, and he runs the town like a corrupt riverboat captain. He knows every move that every person in town makes, anticipates problems and eliminates them. His girls aren't exactly the class of the town, but he controls the most successful bar and whorehouse in all of Deadwood—bringing in $5,000 a day in 1876—and anybody that threatens his sources of income may well end up fed to Mr. Wu's pigs.
Tim Driscoll, who helped facilitate Al's swindle of the city dude Brom Garret, met such a fate, as did Persimmon Phil, who deeds as a road agent brought too much attention to Al's enterprise. Garret himself was killed at Al's behest, though Swearengen eventually abandoned his efforts to retake the Garret claim. And when Mr. Wu came to Al to avenge a murdered opium courier, the saloon boss took care of things by personally drowning the guilty junky.
But Al's hands-on approach has earned him some enemies, and his main commercial rival, Cy Tolliver—proprietor of the more upscale Bella Union—is exploiting the Wu situation to fuel a full-on race war in Deadwood. Al suspects Tolliver of trying to expand his turf.
With outsiders expressing an interest in the wealthy outpost and government soldiers threatening to bring civilization to town, Al is under siege from several directions. And when the territory's magistrate threatens him with an outstanding murder warrant from Chicago, Al decides that the official is not to leave Deadwood alive.
For all his Mephistophelean qualities, Swearengen does have a soft spot for certain people, including the whore Trixie, Jewel, his handicapped house servant, and the brain-addled Reverend Jim, whom Al was forced to euthanize.