Rocks D. Xebec is arguably the largest threat the World Government has ever faced, with knowledge of their secrets and the power to do something with them, so naturally, they’d want him dealt with swiftly. However, bringing him down was easier said than done, requiring the help of an unlikely duo: Monkey D. Garp and Gol D. Roger.
Although they found mutual respect for one another, Garp and Roger spent years as enemies, with the Marine Vice Admiral hunting down the King of the Pirates. However, thirty-eight years before “One Piece,” they set aside their differences, forming a temporary alliance to stop Rocks from taking over the world. The Marines and Roger Pirates intercepted the Rocks Pirates at God Valley, protecting the World Nobles on the island from Rocks and his crew. It took the combined strengths of Garp and Roger to take down Rocks, who died during the incident, with the Rocks Pirates dissolving afterward.
For his role in taking down Rocks, the World Government dubbed Garp the “Hero of the Marines,” offering him a promotion to admiral, which he repeatedly declined. Although Roger played a vital role in defeating Rocks, the World Government erased his involvement in the incident, leading to Garp despising his newly-acquired title, as it made it seem like he single-handedly killed Rocks.