The Babylon is a 'gang' who are the main rivals and work against the Brotherhood of Jah Army of Love gang led by Brother Marcus. The 'Babylon' is the American government, who are attempting to shut down the Brotherhood and regularly attack the Brotherhood and their activities.
Brotherhood of Jah Army of Love
The Brotherhood of Jah Army of Love, also known as the Rastas, is a gang that is based in Vice City. The gang is at war with the Babylon gang and corrupt VCPD police officer Samuel Deever. The leader of the gang is Brother Marcus. The gang controls the drugs trade in Vice City and is known to use extreme violence.
Sonetti's Gang is a gang that appears in Liberty City. It is run by Sonetti, a man who the game's protagonist works for. Their main rivals are the Vercotti Gang It is believed that Sonetti was killed in a bombing though it is never proven.
The Mob is a small-time gang in San Andreas. The gang is led by Don Traegeri and are enemies with Uncle Fu's Gang. Traegeri and The Mob were wiped out eventually by the protagonist along with Chow Yun Thin.