Global Defense ForceThe Global Defense Force (GDF) is a paramilitary international rapid-reaction force formed from the various national armies and relief agencies in reaction to natural and terrorist disasters of the early 21st Century. It is the only military force with the equipment, command structure and mobility to defend Earth from the Strogg invasion. The GDF forces are humanity's brightest and best; they represent Earth's first and only line of defense against the pitiless Strogg raiders.
SoldierSkilled with heavy weapons and explosives, the Soldier is your basic assault unit. He is best-suited for attacking roles or defending teammates while they complete key objectives. The Soldier can choose heavy weapons, such as the N93 General Purpose Machine Gun (GPMG) and N72 LAW Rocket Launcher. He also carries Fragmentation Grenades and the High Explosive Charge
Field OpsThe Field Ops can provide ammunition to the other classes as well as being the only class capable of using of long-range bombardment deployables. The GDF's Fire Support specialist, the Field Ops can deploy Fire Support guns in the field, and designate targets for them. His deployables include the Artillery Gun, Guided Rockets, and Strategic Hammer Launcher. He can also call in Air-Strikes and dispenses ammunition to his squad mates. He carries the N80 Assault Rifle.
EngineerThe Engineer is a support/defense class, constructing and repairing vehicles, deployables, and objectives (such as bridges and machinery). He also deploys and maintains defense turrets, such as the Anti-Personnel, Anti-Missile and Anti-Vehicle deployables. The Engineer carries the N22 Shotgun and multi-purpose mines.
Covert OpsThese elite operatives are able to use long-ranged sniper rifles and to gather advanced intelligence on the enemy. Often critical to mission objectives, Covert Ops can disguise themselves as fallen Strogg enemies and also hack Strogg technology to serve GDF needs. Rangers can use their PDA's to hack and disable enemy deployables, and deploy 3rd Eye cameras to spy on the enemy and relay their locations to his squad mates. The Covert Ops carries the N38 Sniper Rifle and smoke grenades.
MedicIn addition to providing med packs to soldiers on the front line, medics can also revive unconscious combatants. The Medic is a key supporting class, attacking any threats, but mainly maintaining the health of his teammates. The Medic can air-drop supply stations in the field, and carries the N80 Assault Rifle.