The O'Driscoll Boys is a hostile gang encountered by the Van Der Linde Gang in Red Dead Redemption 2. Led by Colm O'Driscoll, the gang has been around for almost as long as Dutch's Gang and the two groups have been rivals ever since.
The O'Driscoll Boys gang was founded by the Irish-American outlaw Colm O'Driscoll around the same time as the Van Der Linde Gang. The two gangs eventually developed a rivalry that evolved into direct hostility. The policies and rules of the two groups were significantly different, leading to their incompatibility.
Unlike Dutch's Gang, the O'Driscolls had no qualms about murdering innocents, including women and children, during their capers. Colm favored a looser but larger group, caring more about the number of recruits rather than their character or skills. As a result, lower-ranking gang members were considered expendable and easy to replace, however this made the members less loyal to their leader or one another. The average O'Driscoll gang member wasn't particularly learned or skilled in combat, and the Van Der Linde Gang's members easily dispatched them on most occasions.
Colm O'Driscoll seemingly favored recruiting Irish immigrants, and the gang's color was green.
Events of Red Dead Redemption 2
The O'Driscoll Boys are first encountered in the opening scenes of the game. As Arthur, Micah and Dutch ride to a small homestead hoping to find shelter and food from a snowstorm, they find members of the rival gang already there, and a corpse stowed in a cart.
After killing the O'Driscolls, it turns out that Sadie Adler, the wife of the dead man found earlier, survived by hiding in the cellar. Micah accidentally sets fire to the homestead, burning it down. The outlaws, along with Sadie who then joins them and an O'Driscoll survivor escape, with the latter revealing that the gang was planning on a train heist.
Later, Dutch leads a raid on an O'Driscoll camp which leaves many of their members dead. On the way back from the raid, Arthur captures Kieran Duffy, an O'Driscoll recruit who has become disillusioned with the gang and dislikes Colm and his tactics. Kieran is taken back to the Van Der Linde camp and interrogated by Dutch, Arthur and Bill Williamson. As a result, Duffy leads the gang to an O'Driscoll hideout where Colm is allegedly residing.
Dutch raids the location and once again many O'Driscolls are killed but Colm isn't present. Kieran saves Arthur's life by shooting an enemy gang member in the head, which earns him his place in the Van Der Linde Gang. Happening concurrently, Micah encounters O'Driscoll recruits near Strawberry and gets into an altercation leaving two men dead, which lands him in jail. Arthur springs Micah, but the two once again run into the rival outlaws when they try to rob a stagecoach.
After these violent encounters, much to Dutch's surprise, Colm offers to parley. In spite of his suspicions, Dutch agrees. However, the meeting turns out to be a trap and Arthur is captured. Morgan escapes, but in his stead the O'Driscolls capture Kieran. They torture him for betraying them, and kill him after learning where Dutch's camp is. They send the brutally mutilated corpse of Kieran to the camp before attacking it. After the attack is rebuffed, the O'Driscolls aren't encountered again for a while.
During the events in Guarma while half the gang is away, Sadie embarks to hunt down the O'Driscolls for what they did to her husband and home. When the gang is once again reunited, Sadie just happens to be chased by a group of O'Driscolls whom Arthur promptly kills.
Some time later, Colm O'Driscoll is found and arrested by the authorities. Incarcerated in Saint Denis, he is scheduled for execution but his gang is planning to rescue him. Arthur and Sadie, along with Dutch, intervene and shut down the O'Driscoll outlaws, thus foiling their plan which results in Colm being executed as planned. Sadie then kills the O'Driscolls which leads to a shootout.
Later, Sadie will ask Arthur's help to eliminate the O'Driscolls once and for all. They travel to Hanging Dog Ranch where they confront and kill Tom O'Driscoll, brother of Colm and the man who killed Sadie's husband. After this happens, the O'Driscolls cease to be a force worth mentioning in the West.
The O'Driscolls are seemingly designed to be an antithesis to the Van Der Linde Gang. They mass-recruit instead of being a small but tight-knit group, and care not for the lives of innocents while Dutch's Gang generally tries to fall on the just side of crime.