History: (Green Lantern IV #4, Green Lantern / Sinestro Corps: Secret Files #1) - Following the defeat of Parallax the Guardians were reforming the GLC, sending rings to the 3,600 sectors of space and bringing back recruits to Oa. Grumb was a soldier in the Nameless Army when he was recruited and recalled to Oa, becoming a Green Lantern. He stayed nameless until a few months of training under Kilowog, and he came to dream of being a drill instructoir like Kilowog. Grumb and Kilowog’s other trainees watched a meeting between Green Lantern Hal Jordan and Kilowog. The new recruits were taken aback by Hal because they though all Earthmen were backwards and primitive. Hal realized they had no idea he’d destroyed the last GLC, and Kilowog reminded him that the universe was a big place, and in the big picture Hal wasn’t that important.

(Green Lantern IV #25) - The Sinestro Corps War raged on Earth, and while Grumb, the GLC and an army of superheroes battled the Corps the Anti-Monitor prepared to unleash an anti-matter wave to destroy Earth. With Earth’s destruction, the entire 52 would fall, and he would once again rule all that was. The GLC ruptured the heart of Anti-Monitor’s Warworld, the Sinestro Corps central power battery, and created a shield around Warworld and the Monitor. The ensuing blast nearly destroyed the Anti-Monitor, and he was finished off by Superman-Prime, who betrayed him for having destroyed his home, Earth-Prime. GL Hal Jordan defeated Sinestro in personal combat, and the Sinestro Corps, lacking any leadership, fled Earth. The heroes rejoiced and began rebuilding the damage the Sinestro Corps did.

Grumb received a profile in Green Lantern / Sinestro Corps: Secret Files #1.