Ze History

The U.S. government thought it sounded like the perfect weapon, a highly dangerous mutagen virus that could actually turn the enemy against themselves.
That was until when a terrorist organization got a hold of it and proceeded to spread it worldwide using various methods- from fake vaccinations to tainting fast food.
The virus mutated, turning those it infected into horrid undead monstrosities.
Anarchy soon spread. Bombs, nukes, napalm and the works fell from the sky, but the dead still stood. Armies were deployed, firing all they had, still the dead stood. The once great cities of the world were now in ruins as the remaining survives fought living and dead alike for the world’s depleting resources.
And so it has been for half a decade.
This war cannot be won by traditional methods. The only way to win is to survive or die trying.