Backup

In Grand Theft Auto: San Andreas, the feature of recruiting gang members was added. This feature was added again in Grand Theft Auto IV, but can only be unlocked if Dwayne Forge's friendship is 75% or higher.

Grand Theft Auto: San Andreas

To recruit Grove Street members in Grand Theft Auto: San Andreas, you must aim a gun at them and then press up on the D-pad on Xbox or up on the Directional Buttons on PS2. They will kill rival gang members and kill anyone you attack.They carry a pistol or a TEC-9.If the player chooses to find all the Gang Tags all backup will instead carry a MP5 or a Desert Eagle. They will also attack cops if they are chasing you. Its possible to activate a cheat to recruit anyone (including rival gangs) to join you. For example, if you recruit some Ballas, they will attack Grove Street and Varrios Los Aztecas members. A rare glitch affects this cheat were if you recruit these gangs they will attack their own gang.

Grand Theft Auto IV

The only way to get backup is to get Dwayne's relationship to 75% or higher. Once that is achieved, he will send backup on request. 2 gang members come, and will assist you.One will always carry a Micro Uzi and the other will always carry a pistol. The gang members will only attack others if they attack first or if you attack them first, and will also attack cops, but only if they attack you.Niko's two backup men have very high health being able to take ten Combat Shotgun blasts at point blank range before dying.

Grand Theft Auto IV: The Lost and Damned

When doing a Gang War Johnny gets six gang members who help in the war.Two of these members are always Terry and Clay.The other four random members can have their 'toughness' go up by doing gang wars and surviving.With increased 'toughness' the members get increased health and get better accuracy.Later in the game the player gets the option to call Terry and Clay as backup.By doing wars,friend activities,and just by surviving random gun fights Terry and Clay's 'toughness' will go up upgrading their health,accuracy,fire rate,and their weapon.Terry's weapons are the SMG,the AK-47,and finally the Carbine Rifle.Clay's weapons are the Pump Action Shotgun,the Combat Shotgun,and finally the Assault Shotgun.

Grand Theft Auto IV: The Ballad of Gay Tony

When doing Drug Wars Luis is accompanied by Armando Torres and Henrique Bardas.The more Drug Wars the player does the better their backup's weapons get.Eventually Armando and Henrique will carry an M249 and a Gold SMG.Tony Prince also serves as backup in the mission Party's Over with a Pistol .44 but mostly he only does blind firing.

Trivia

In Grand Theft Auto: San Andreas after the mission Riot a glitch happens when you have backup.Sometimes your backup will run as far away from CJ as possible even jumping out of the vehicle they are currently in and running away.
In GTA IV when you get in a car with your backup the one with a Micro Uzi will always ride in the passenger seat while the on with the pistol always rides in back.With that in mind when getting on a motorcycle the one with the Micro Uzi will always get on back with Niko.
Niko cannot call for backup during and after the missions If the Price is Right and A Dish Served Cold.
In GTA IV if the player is in a gunfight the player can call 911 to have the police come over and shoot at Niko's attackers.
Patrick McReary and Phil Bell serve as backup in some missions.
Jim Fitzgerald also serves as backup in some missions before Was It Worth It?