O'Brien served Bruno Borgia and his gang. He was also responsible for bringing Bruno's pregnant wife Isabella Borgia to a nearby museum. On the night when Isabella went into labor, O'Brien met with his boss and explained that he helped bring Isabella to the museum and set her up inside safe and guarded.
Bruno ordered that if he was to kill off every single mob boss and their goons by the night's end, he would be given as Bruno puts it "All of the privileges". Warning him that he shouldn't go and ally himself with the Irish gangs, O'Brien assured Bruno that he and the Irish have had their differences and therefore the death of Broken-Face Finlay and his men would be "Settling Old Scores".
He ordered his men to kill all of Bruno's enemies and sure enough, this attracted the attention of the Yautja named Scarface. He and the rest of his men remained inside the museum protecting Isabella, Bruno and their future son Hunter Borgia. O'Brien and his men were eventually killed by Scarface.
- Predator: Concrete Jungle (video game)