The World Falls to Darkness

In the year 0 ATF, the world fell under darkness. This does not mean that the sun isn't there anymore. It also doesn't mean that the entire world has fallen. Instead, the huge majority of civilization has fallen. A few bastions of survival remain, generally guarded now by thousands of strong warriors, and kept alive by a single great miracle worker. However with the strength of the evil this is doomed to not last.   The evil that is appearing come from weird Monster Rifts in reality. First these tears in reality appeared underground and they pushed the dwarves out of their own tunnels. When these rifts reached the surface, it was not long before they overwhelmed the normal population. At first, the strength of the forces was only in number, there were millions of them, dotting out the landscape. They wiped out most of the rural population, and laid siege to cities. While the fact that Sospitator, previously known as Urgava, was announced to the world that it was still standing and accepting all refugees, other cities weren't so lucky. Any and all people of strength could survive against these creatures, especially if the adventurers were few in number, and hundreds upon thousands of them made the dangerous trek to Sospitator in the ensuing years.   Each of these dark warps in reality our magicians have determined lead to a pocket dimension, from which these strange creatures came from. It is unknown who created these creatures or these dimensions, but what is known is that if we enter the dimension, and purify it of darkness, it will shortly after disappear. Unfortunately, these portals are still appearing all over the world, and the forces of darkness are only growing.   The remaining cities are named, Sospitator, Onauern, Bega, and Cyre. Each independent from the others, and believe that they are all thats left.   Unfortunately, in recent years, the creatures have been becoming more dangerous. Becoming stronger, faster, smarter. All that remains is for them to destroy the last few cities, and with these new developments, who could stand against them?