So far this campaign setting exists more as a series of notes and ideas rather than anything else. But I figured I might put out the notes and just see if I could get feedback on the campaign setting ideas, maybe what sounds most interesting to people and what sounds least interesting or what you might suggest changing.
The 3PP I'll be drawing from is the Spheres book (totally replacing standard casting) as well as (possibly) the Pact Magic and Akashic Magic books. I'm not totally sold on those though I think Akashic Magic might have a pretty good place in the world.
And the notes:
So the Githyanki invaded the world about a hundred to a hundred and fifty years ago. They began conquering / destroying parts of it, while the world looked to mount a defense. The elves, who controlled the largest school of magic and the webway (magical set of tunnels that allowed nearly instant transport anywhere in the world) it sat on top of, used exceptionally powerful planar magic that got out of hand. They shut the webway down but it had already triggered an apocalypse of sorts. (Volcanos, tidal waves, kaiju unleashed, etc.)
The elves lost their vaunted immortality. They now age and die within 30 years of birth. Their immortal queen lies dead but magically preserved in a glass casket that elves are allowed to gaze upon. Some elves are focused on necromancy or time (or both) in an effort to regain their immortality. Other elves are just focused on fighting off the Githyanki.
Sphere magic changed, arcane magic now either preserves or defiles. Divine Magic now has a chance of wild magic. Psionics, the newest form of magic, draws it’s power directly from the lifeforce of the user.
Pact magic has been unaffected by the change in the spheres. Akashic magic actually seems to be on the rise.
Dwarves have long fought against an Illithid empire under the earth. The mind flayers were winning, but since the Githyanki invasion, the Githyanki have joined the Dwarves in battling the mind flayers. They are on fairly friendly terms.
Another occurrence since the apocalypse is that the souls of the deceased have no where to go. If the bodies of the slain are not properly buried and funeral rites performed at dusk or at dawn their bodies will disappear and they will come back the next night as undead. The undead don’t come every night, they seem to be pulled by an invisible (or black) moon (like a magical tide) that people have only noticed by watching stars flicker and disappear then re-emerge.
In the last 50 or so years dwarves who had been enslaved by the Illithid mind powers have began showing the ability to effect minds themselves. This magic is spreading like a virus almost. No one who hasn’t been the target of mind magic may develop mind magic. (Ie. The mind sphere.)
The magical webway is now sealed and barred. It can only be opened from the physical location of the school, which exists on the Warp Magical Well. (Magical Wells are places where spheres are super empowered, there’s no more than one for each sphere, and not even all the spheres locations have been found.)
The Githyanki are still a threat to most races, but a lot of the setting (and the game) would be focusing on dealing with the fall out from the apocalypse and trying to reclaim what was lost before it is lost forever (or worse, falls into Githyanki hands).