The Gorilla Army is a group of Mobian Gorillas known to inhabit the Mobian Jungle, where they lived peacefully for many years. Like most of Mobius' inhabitants, however, they were later forced to take up arms in order to protect their home from the predations of Dr. Ivo Robotnik. They have since become allies of the Knothole Freedom Fighters.
When Dr. Robotnik began his rise to power, the Gorillas opted to maintain their peaceful ways, believing the jungle would keep them safely hidden; only the one who would come to be known as Sergeant Simian wished to fight back, which eventually caused him to leave on his own. However, the doctor's increasing campaign forced the remaining Gorillas to become more warlike, transforming their village into an armed camp. Simian eventually returned and was made aware of the change in his people, who offered him his sergeant position; he accepted the title, but refused to remain, feeling that his people were unworthy of him. (SU: #30)
As a result of the change in their nature, the Gorillas greeted Sonic the Hedgehog and Rotor of the Knothole Freedom Fighters with suspicion upon their arrival in the jungle. Both were held prisoner, and Rotor was to be forced to cook and create weapons for the hostile group. Sonic attempted to trick them by offering them a cache of weapons and then stealing from their own warehouse, but his ruse was discovered. Later, the Gorillas were left terrified by the approach of Robotnik's Eco-Destroyer, though many had been knocked out by a stew Rotor had filled with Narcolyptus Berries. Fortunately, the Knothole Freedom Fighters—with help from their prehistoric friend Mobie—were able to defeat Robotnik's machine, thus establishing peace between them and the Gorilla Army. Mobie also took up residence with the Gorillas, happily joining in their watch over the jungle and adding his considerable might to their arsenal. (StH: #45, CSE)
- Apart from the Gorillas found in the Mobian Jungle, two others have been encountered by Sonic and his allies: Knuckles the Echidna's childhood tormentor Monk, and the former bouncer of the Bottom of the Barrel Bar 'n' Grill. It is unknown whether they are also from the Mobian Jungle, whereas Sergeant Simian-originally thought to be unconnected to them-was revealed to have originally been a part of the group.