The religious ways were quickly abandoned as every zombie grabbed the nearest weapon. Soon, religious disputes turned into skirmishes, which in turn became a full blown war. At first, the zombies tried to cooperate, but soon religious disputes arised - the Sergeant clan used the stealthy Way Of The Shotgun, while the Commandos worshipped the brute force Way Of The Chaingun. Former humans possesed by evil spirits, these mutants were abandoned on the planet when they lost their purpose for the overlords of hell. The invaders from Hell left shortly afterwards, leaving behind the remnats of an extinct civilisation. Without its protector, humanity fell in less than a week. Despite breaking two more sieges to Earth when old enough to be a grandfather to everyone else in the marine corps, he eventually died of old age, and on the same day, Hell attacked the blue planet once more. However, not even the marine was spared from the greatest enemy of all, time. In the Phobos Anomaly, Hell on Earth, TNT and Plutonia incidents, there was always the one marine who could survive where other could not, wipe out entire legions of demons and stop entire invasions dead in their tracks.
No matter how many times Hell invaded the Earth, its forces were repelled every single time.