Premise: Brave knights enter the burnt ruins of a dead city. They naively believe good will triumph over evil. Slowly they become jaded and succumb to despair. There is no glory here; only death.
Fifty years ago a mighty dragon swooped down into the city. It was the day of the princesses' wedding. The streets were packed with celebrating city folk. The dragon killed a thousand people in mere moments. As the city burned the dragon gorged itself and then, finally satiated, it tunnelled into the palace ruins and built a nest.
The dragon still sleeps to this day, periodically giving birth to monstrous offspring as it slumbers. The dragon's horrible spawn are lesser but still ferocious monsters: drakes, wyverns, manticores and chimera. These loathsome beasts have spread throughout the ruins and made their own lairs.
In places fire still burns. Dragon fire is magical, stone that is bathed in it may burn eternally. A huge cloud of ash hangs over the city and the sun has not been seen there at all for half a century. Periodically flashes of lightning arc through the clouds and deluges of oily black rain pour from the sky.
Ash coats every surface, staining everything grey and black. Great drifts of ash accumulate in alleyways and dark corners. Adventures cannot help but to breathe the ash into their lungs, causing a painful wracking cough. The ash gets into eyes, eventually causing blindness.
Knights and Heroes come from far and wide, each believing naively that they will be the one to finally slay the dragon and retake the kingdom. Their romantic dreams of heroism are crushed and their souls are tainted black, even as their bright heraldry is stained black by the falling ash.
Taste: Oily smoke on the air. A lungful of choking black ash. Tainted water. Stringy mouthful of crow meat.
Sound: Metal on stone. Swords clashing. Echoes of the past. Moans of despair. Chains clinking. Eerie stillness. The bellow of a monstrous beast. Rumble of far off thunder. Ash falling like snow.