The Moving Poles (and some theory)

The frigid polar region corresponding to the Earth's Arctic Circle (that area which receives at least one 24 hour day of full darkness) is about 4,000 kilometres across. This zone shifts constantly at about 100 km per year, meaning that over an average person's life-time (say 70 years), the climate can shift from polar Arctic, to sub-Arctic and into temperate zones - or almost two full climactic zones. There can be one zone-shift in as few as 40 years, or a zone could persist as long as 120 years, depending on how obliquely the zone moves over the observer.

However, it is possible (and quite likely) that the pole will transit obliquely to any one spot on the surface, and not pass directly over that spot for hundreds of years. This could mean that a particular climate could be over one spot for a considerable period of time - perhaps centuries, or that more likely, an area oscillates around 2 or 3 climates for a few centuries before being thrown into the deep freeze.

The poles oscillate (or wobble) about the surface of Angadurgh in an overlapping sinusoidal fashion, ultimately tracing the entire surface over time. The appearance of the planet from space (if sped up) would look like a spinning top as it decays - wobbling in a circular fashion with a certain pattern to its seeming chaos.

The Dying Cities

Jak dove to the ground in mid stride hauling his sister down behind the fallen log, as he wrapped his cloak around her face to muffle her cry. He struggled to control his own ragged breath as he took out his Gun and removed the oily rag covering the priming pan. The things that hunted them were far enough away (he hoped) that they would not have seen them drop out of sight. Jak and his sister had been running for the best part of an hour, deeper and deeper into the forest. The shadowy creatures followed, always at the edge of vision, flitting from tree to tree, ever closing.

It seemed like ages had passed since they had been sitting together in the family tower. Jak leaning against the window and gazing over the interminable forests as his sister bemoaned her fate. Their step-father, never the diplomat had announced her betrothal just the day before, with the wedding itself to be in two weeks time. Just long enough for the groom's family to travel from the nearest city-state rival, Kellinstat. Jak had always wondered what lay beyond the next hill. What it meant to survive beyond the walls and confines of the dwindling citadel. He hadn't really thought Sarei would agree to his suggestion when he challenged her to run away with him. Right now, he wished she had put up some more resistance.

The cities hold the last libraries above ground, as well as tight clans of old families, generally inbred as well as dangerously paranoid and xenophobic. Around the towers of the highborn cluster ramshackle cottages and tightly packed terraces of houses, where dwell the serving classes, artisans, and merchants who deal with the outside. Highborn of the cities tend to be educated, and have access to certain technologies such as arcane magic of the Wizardly variety, and alchemy such as black powder, steel, primitive steam driven machinery and coal-gas. Use of these and other technologies is by no means widespread in the cities, but neither is it unheard of. Most of the tools and dies used in the creation of the technological items are ancient beyond knowledge, and cannot be re-created by any techniques available at present, but there are dies and diagrams for making crude pistols and blunderbusses, as well as single-piston reciprocating steam engines, crude airships and a terrifying inventory of torture devices.

Rumours exist of even more exotic artifacts in the holding of some of the oldest families - weapons so terrible that whole armies might be vanquished if they only had the key to their function - or the fuel they required.

Divine characters

I have mentioned already that the deities in Angadurgh will be fickle, egotistical and not particularly reliable (although still very powerful).

I see this playing out in a way that divine characters will have to make "concordance" checks, much like those for artefacts. Being "in concordance" makes it very likely that ones divine powers will work as usual. Being out of concordance will make it unlikely. I would actually recommend that players build hybrid characters, so that they can at least draw from their non-divine class when the gods fail them.

The mechanic would be based on a modified d20 roll at the beginning of each encounter (or before using any divine powers such as rituals outside of encounters). If the roll succeeds, all is well, divine powers will work as expected. If the roll fails, then divine powers will be "variable" in result. A roll on a table will determine what happens when a power is used. Results will range from "works as usual, but with a minor non-mechanical side-effect, through simply not working at all, to wreaking significant damage and/or conditions to the caster and those around her.

As for following the wishes of the deities, the DM will have to follow/create plotlines for them. Using their personalities, and some pattern of events taking place in the heavens, one can create a dynamic that would have the Gods demanding certain actions of their mortal followers as they (the deities) jockey for position, carry out vendettas, or vie for prestige in their heavenly realms.