Prologue
The air was filled with the smell of electrified sulphur. It was visible from every part of the Underworld, a warp in reality so big that entire armies could pass through it at once. There was a platform spanning from fortifications of a gigantic black citadel in front of it. A tall humanoid lizard covered with feathers ascended the platform and watched as inhabitants of its dark kingdom gather upon the portal.
Citizens of the Underworld! The long awaited gates are open! Some souls within the mortal world were gifted by the Lords of High Heavens! Their spirits were turned into energy vessels of great capacity! I, Urnash the Feathered, King of the Underworld announce the beginning of our long awaited tournament! The one who would bring me as many skulls of gifted mortals as possible will become the next ruler of these blackened lands! - the dark king have spoken, and after countless screams and howls seen here as applause, the armies moved forth to the portal.
It was a second week of a strange solar eclipse. The blackened sun seemingly started bleeding a dark ooze down the earth, corrupting everything touched by it. People of Churchbury have stocked up on every possible resources and it's only a matter of time before the city would be under total anarchy. The city watch is trying to keep order on the streets, and the Church of Nix is supplying people with anything that they can give. A dark, stormy cloud covers the entire sky. People think that it's a godsend after two weeks of scorching heat. But then the lightnings started tearing the realm, opening countless gates between the mortal world and the Underworld. Demons, dark spirits and the undead quickly launched an assault on nearly all existing settlements at the same time.
The great horde approached the gates of Churchbury. Anyone brave enough to defend the city was armed and sent to the fortifications. The last influx of peasantry fleeing from smaller village and travelers from far lands was allowed inside before the gates were closed for good. Then, the siege began...
GM Notes
You may start at: Fortifications, streets, random building, outside the city walls (challenge), in front of city gates and in the Church of Nix.