The Black Arm Gang is a gang at war with the Phoenix Gang. Their base is situated in the south-west of Varrock, near the city's southern entrance.
According to the Phoenix Gang leader, Straven, the Black Arm Gang was formed when some Phoenix gang members mutinied and branched off into a separate gang. They broke the Shield of Arrav in two during the process, taking one half with them.
During the events of the Shield of Arrav quest, players can choose the Black Arm Gang or the Phoenix Gang in an attempt to retrieve both halfs of the shield at the request of Reldo.
During Heroes' Quest, players seeking the thieves' armband must steal ScarFace Pete's Pete's candlestick for Katrine.