Riggs is part of the Strike Force in the Campaign. He's a Commando, and you usually see him laying heavy suppressive fire on your enemies. Since he is a Commando, he basically has machine-guns and rocket launchers at his disposal. His specialty is in the amount of ammo that his weapons has. He usually has few deaths and a moderate amount of kills. You almost never see him reload, since he is equipped with Ammo Feed. Riggs' voice is American, slightly deeper than Toad's.
Riggs usually carries the S.A.W. (Squad Automatic Weapon), but is sometimes spotted using other weapons like:
Abilities and Tactics
As a Commando, Riggs is able to use the killstreak Tear Gas, lowering their enemies' accuracy and making them unable to see anything. He also uses the Ammo Feed skill, which means Riggs will be able to fire forever (or at least until his whole supply of bullets run out) without needing to reload and therefore has no vulnerability. (Except when suiciding with the explosives)
Of all the Strike Force members, Riggs is the least vulnerable. His Ammo Feed makes him hard to kill without getting shot, and he can help you kill enemies easier with Tear Gas, since he has excellent weapons.