Gargantua is an African-American man with quite a hot temper and a sense of power. He commanded his fellow raiders to attack a village called Dirt Haven, which was under protection of the Brotherhood. This led to an assault on his main base in Devil's Graveyard.
He was confronted by the Brotherhood's initiates when nearly all his men were killed, including Psycho and the ones led by his lieutenant, an unnamed raider leader, in Dirt Haven. Gargantua was very pissed off by the fact that his enemies were only initiates, and not the paladins who he expected to see. Then he was killed.