The world is positively charged. Extremely. There are islands that are highly positively charged on the bottom, and negatively charged on the top. The two positive charges repell eachother, with force equal to gravity, and so the islands are suspended in mid-air.
I have two possible additions to this. I'm not sure which I want.
1) The water on the tops of islands evaporates, creating negatively charged clouds. The clouds drift away from the island, and now have an extreme positive charge below the,, istantly emitting a bolt of lightning. Except when they pass to below the island, the positive charge on the bottom attracts the lightning. So lightning curves from the sky to the bottoms of islands, which is really cool. Positive clouds would remain under the islands.
There would also be birds, which can gather negative charge in order to float above the islands. If they fell off, they would be attracted to the bottoms of the islands, and climb back up. They could discharge their energy in order to sink back down, or not be smashed so hard against the bottoms of islands.
But one issue is, that means that the islands are constantly balancing. The tops are getting less negative, and the bottoms are getting less positive. If this has been going on for a long time, the islands should have become neutral and fallen already. I would need some way to repolarize the islands, and I don't want to use magic or technology.
2) The islands are actually completely positive, and there is no lightning that balances them. The moon, however, is extremely negatively charged, but orbits in such a way that it never falls. As it passes over an islands, the island raises up slightly, as it is attracted to the moon.
Recently, some disaster (probably a meteor of some sort, or a malevolent force) blasted the moon, and since then pieces have been falling off. As they get close to the islands or the ground, the negative charge is attracted to the positive land-mass, and a bolt of lightning strikes. People would calss lightning "lunar energy" or something similar because of this. Eventually, enough pieces could cause an island to lose its charge and fall to the ground. Since this hasn't been going on for millenia, this is a plot point, not an inconsistency.
The only problem is, I like the curved lightning and charge-based birds.
The society will be sort of tribal, and they may use higher technology than they really understand, either given to them by a more powerful nation, or more likely found from a civilization that was destroyed.
I'd also like some reason for people to have to decend into the very dangerous surface world, perhaps in order to collect energy or food.
I'll post more on society later, since I have to go, but does anyone have any comments on this so far?
It is touching it can cause Electrical damage, and it can be used as a focus for electrical spells (after some enchantment)
Certain plant like creatures feed off electricity. give it a new type, Same dice as plants, some immunities, electrical healing, high ref, low con and will, shambling mounds may be moved to this type.
Air ships work by placing ChargeStones in masts made of Pumice and Wood. Metal connectors are applied to bleed charge and lower the craft. Flipping a craft is suicide.
Mix it with a bit of Ebberon and some stempunk. Electricity is the big theme for the setting so you could build some more creatures based of that.
Maybe negative and positive (charge) elemental planes, connected to the magnetic planes, the positive and negative life energy planes and the (fire and water planes). They form a hyper cube that surrounds the material plane and protects it from the outer plane's influence.
I think I'm gonna go with my option 2, with the lunar lightning. So all of the islands and the planet surface are positive, and the moon is negative.
I may end up with some kind of material that can draw, and more importantly, discharge, positive charge, which flying things can be made out of. Probably some sort of "moon stones."
The current idea is, the moon has a positive charge as well, but there is another planet in the solar system that is extremely negatively charged. Recently, the planet was destroyed (not sure why yet), and the rocks have been bombarding the positive planet for a hundred years or so. When the initial wave of negative rocks passed the moon, of course some serious discharge occured (especially since the moon is gonna have an atmosphere, which is conductive). So the people observed the moon exploding in lightning, and therefore believe that lightning comes from the moon.
I like the idea of plants that feed on charge. I think I'll have one type of plant that produces negative charge for some reason. Not sure what yet. But the idea is that is gives something to discharge to. Maybe that's why. It feeds on positive charge, but drawing it out of metal is hard, so it makes a negative charge, so that when all these birds and things that build positive charges need to discharge in order to land/decend, it's like a free meal.
I think I'll also have lizards that build negative charge in order to stick to the bottoms of islands.
I doubt I'll have any sort of planar travel, just since I want to emphasise the craziness of the world, and the idea that the people need to protect it, 'cause there isn't anywhere else to go.
Society is gonna be pretty small, but they'll have lots of remnants of some larger societies that came before that were most likely destroyed when the initial blast of negatively charged rocks fell. I'd like to avoid "airships," but perhaps smaller stuff like gliders and things, for personal use.
Cleric
Clerics in this world are called shamans, and most of their radiant spells would be lightning, cold, acid, or poison. They use the elements and nature as a source of their magic, but I feel like the cleric class features and powers fit very well statistically. Sort of mystical leaders of their people. But they'll need something to replace chainmail armor proficiency. Replace Religion with Nature. Religion is still a class skill.
Fighter
Fighters are generally known as martial artist, but are otherwise pretty standard. They'll also need something to compensate for lighter armor.
Paladin
Paladins are known as savants, and they channel shamanistic magic through weapons. Again, they'll need compensation for armor. Replace Religion with Nature. Religion is still a class skill.
Ranger
Rangers are trackers and hunters, and are largely unchanged.
Rogue
Rogues are often called fortune hunters, and usually work with rangers to hunt and scout.
Warlock
Warlocks are called Diviners, and they draw their power from the spirits, not any sort of pact. Spirit magic is not evil in any sense, but the forests of the surface are filled with spirit magic and dangerous spirit creatures, and people fear it. Nature is a class skill in place of Arcana.
Warlord
Warlords are group leaders, rather than military commanders. They focus more of their time on leading small groups of hunters than leading soldiers or planning battles. Nature is a class skill, and they need compensation for armor.
Wizard
Wizards are called sorcerers, and they are effectively the same. They use formulae, research, and knowledge to manipulate the forces of the world. They are generally mistrusted, but grudgingly accepted, by common folk.
Other
I may use other classes as they're released, and I'd like to make at least one of my own (the Mimic).
But the reason for them can get stale, so I'm using natural physics instead of magic/science.