WW Expansion Version:
In the middle of the twenty-first Century, extreme nationalism led to the Third World War. The outbreak of war has made all countries use advanced weapons of war, and some countries even use nuclear weapons for their benefit. In order to counterbalance, non nuclear countries have produced highly contagious biochemical weapons.
nuclear radiation, virus continue destroying each big city in the world, the unconscious patients began to run the streets, a large number of zombie attacks on civilians make the virus spread speed. Governments, troops and hospitals are unable to cope with the forced disband of escape, leaving only a few of the community armed groups to resist.
however, the people live in order to compete for resources and limited land, still crazy to kill each other, the world has become a hell on earth.