Sergeant Major Guy Cunningham, call sign "Ratzass," was an elite Mobile Infantry trooper in the Roughnecks K-12 team. His personality was straightforward and impulsive, marked by a disregard for personal risk, crude humor, and overt flirtation—especially directed at female comrade Ice Blonde. This behavior culminated in a locker room incident where Ice Blonde exposed herself fully and walked away, leaving Ratzass speechless while teammate Bugspray laughed. Ratzass fought in the Fort Casey mission under Minister Carl Jenkins's orders to capture a live Arachnid Queen, suffering heavy K-12 casualties but surviving to be evacuated aboard the Alesia. During transit, he openly resented Jenkins for assigning the "death run," ignoring Bugspray's warning about Jenkins's influence. Later, he instigated a fight with A-01 trooper Chow by mocking his martial arts as "dancing." Though initially outmatched, Ratzass knocked Chow down after Ice Blonde exposed her breast, distracting and motivating him; both combatants ultimately collapsed. When General Johnny Rico ordered a mission to find the missing John A. Warden, Ratzass demanded their arrested commander, Major Henry Varro, lead it—a condition Rico accepted. Boarding the infested Warden, Ratzass witnessed the deaths of most K-12 members—Kharon, Gunfodder, Holy Man, and Bugspray—to Arachnids controlled by a Queen Bug. He helped set charges in the engine room and survived the starship's crash on Earth. Before the final assault on the Queen, he assured Ice Blonde she would see her daughter again. Ratzass escaped the exploding Warden on Jenkins's shuttle, paying tribute to fallen comrades while watching the wreckage. Promoted to Sergeant Major, Ratzass transferred to the starship Nemesis under Colonel Rico. During an emergency evacuation, his power suit helmet failed to seal during a high-altitude low-opening jump, killing him via vacuum and extreme cold exposure. Ratzass typically wielded a Morita Mk III SAW, switching to a twin-barreled Gatling gun in intense combat. His call sign reportedly originated from his perceived indifference to danger.