I've literally been straining my brain for the past few days on this homebrew.

[Gilligan]

This setting/campaign idea has been running through my head for some time now. It started out as my attempt at making a setting that once had magic and gods, but no longer does. As if Ao got sufficiently pissed off at the gods of Toril and decided it wasn't worth the fuss.
When I went about trying to make it I realized I couldn't let anything go unanswered and had to make it as awesome as I knew it could be. In pursuit of this I felt kind of odd asking a guy at a gaming shop if he knew anything about planescape and it's politics to help me with a godless and magicless campaign.

I'm having to revise my perspective of how magic (divine and arcane) and psionics work, and how the fabric of the multiverse interacts with them. Here's what I got so far:

In this setting psionics are fundamental, but understanding psionics and tapping it in a disciplined manner requires a deep understanding of the nature of the universe and it's relationship and literal ties with sentience/consciousness.
Arcane magic is a derivative of it formed by the birth of a being (The Serpent?) whose very mental fabric is spread out across most places in the multiverse, and is able to be manipulated by beings or objects that discover it or whose own being somehow gets interwoven with it when brought into existence. Arcane magic may be relatively easy to interact with, but there's still quite an art and science to it.
Divine magic is polarized positive and negative energy which I guess is the power behind gods that makes them unique. If you take the sum of all the divine magic gods possess and grant, it will cancel out. In other words, it will all balance. Divine magic exists because gods are able to channel and morph tidbits of the power behind them and their portfolios through a metaphorical series of arcane tubes to their more devoted worshipers. By morph I meant fashion into useful spells/prayers and such. If arcane magic fails, so too does divine.

So here's the gimmick. Something happened or was about to happen on this once highly magically developed planet that caused enough powers in the multiverse to decide that they had to immediately and without notice transport the planet to a zone in the astral plane where magic is dead and sever all the planet's ties to all other dimensions and planes, making this planet truly alone. Or maybe they're hiding something, someone, or the whole thing. Still figuring this part out!

Anyway the campaign revolves around a Githzerai (or maybe even a Githyanki to make it more interesting) somehow stumbling upon the planet (still don't know these specifics either). He doesn't know why this planet is here or its importance, but he's alone and this place seems like his last hope to getting home. I may have him as an NPC or allow him to be a PC if I trust one of the players enough.

This is all to be done before working on game mechanics, developing a new class or two, figuring out what natural selection has done to the current bestiary, and building hopefully just one continent on one planet from the ground up. I was also thinking of making it an E6 game, at least until it becomes almost necessary for the characters to actually start performing mythical deeds to advance the story.

I have a lot of other stuff in my head but this is long enough. If you have any tips, ideas, or insightful knowledge, I'd appreciate some input.

[Utgardloki]

What, specifically, do you need? It seems that you have a lot of metaphysical data, but I'm not sure what this means to the PCs. Does this mean they don't have magic, that they only have psionics, or does everything work like the rulebook, but this is the metaphysics behind it.

Also, what do you need to figure out? Plot ideas? Explanations for stuff? Solutions to conundrums? Prestige classes?

Ask and ye shall receive.

[Gilligan]

Yeah, sorry.
I guess I'm looking for a nonmagic Ranger variant and a bulked up Expert class that's good for PC's.
Monks I plan on being a big roll in at least some of the cultures. I'm okay with supernatural abilities, just not spell-like abilities. Psionics aren't going to be an option initially for the characters. It's something they'll discover through the campaign.
I'm also open to ideas about reasons for the planet's fate. It will be something that will tie deeply in with the plot so I may end up deciding on my own that specific.

[Kelso]

I like the idea of deities being formed by opposing energies, sort of like matter and anti-matter. It makes a nice explanation of why they don't just try and kill each other. If one deity is destroyed, other opposing deities get a little weaker.

There is a non-spellcasting Ranger variant in the book Complete Warrior.

The Factotum is a PC class very much like a more powerful Expert class. All skills are class skills. They are the ultimate generalists.
Edit: Factotums are in Dungeonscape.

Dungeon Magazine ran a 3.5 adventure or maybe a campaign a few years back all about a Githyanki invasion of a world. That could be helpful.

I own nearly every Planescape product ever published, so if you have a question about that, I can probably help.

[Aratex]

Kobold Quarterly did a spell-less Ranger in issue 11 that was very good. I'd recommend giving it a look.

Edit: The Kobold Quarterly ranger variant is Pathfinder-specific, so you wouldn't have to try to rebalance it to fit with the other PF classes.

[Gilligan]

I am definitely well aware of the magicless Ranger variant in Complete Warrior. I thought it was great. I'm just still getting used to Pathfinder rules (which I love so far), and I'm not sure if the substitutions would transfer over so well. Also, all my 3rd and 3.5 edition books are literally thousands of miles away. Ugh.
Utgardloki, I did focus a lot on metaphysical aspects. I'm a pretty big physics nerd and even though I despise metaphysics when it comes to describing our reality, I'm more than willing to apply that logic to a fantasy setting. Plus, I think understanding this sort of thing in the setting I'm going to run, with the story I'm going to tell, is probably somewhat necessary. At least I want it to be.
Kelso, I'm trying to figure out a political reason to back this. The powers behind this sort of action would make the idea of a simple prophecy seem childish. If you're intrigued enough throw some suggestions. I'll be thinking enough over the next couple days though.
Is there an online source for these classes you guys are talking about, or would I have to purchase the sources?
I'm not gonna lie. I'm pretty drunk right now and I won't be back on until probably Saturday due to work and a social life.

[Utgardloki]

I never met a physics I didn't like.

As for Paladins and Rangers and spells, perhaps you can look through their spell lists, and convert some of the spells into specialized talents available at high levels.

[Kelso]

Gilligan wrote:

Kelso, I'm trying to figure out a political reason to back this. The powers behind this sort of action would make the idea of a simple prophecy seem childish. If you're intrigued enough throw some suggestions. I'll be thinking enough over the next couple days though.
Is there an online source for these classes you guys are talking about, or would I have to purchase the sources?

Maybe their is some sort of artifact on or in the planet that would allow someone to become a god, or to destroy a god, or to steal the divinity from a god? That would explain why the gods might seclude the world.

The Githyanki and Githzerai are not terribly into deities. The Githyanki worship their Lich-queen. Maybe the Lich-queen wants it to become an actual deity, so plans an invasion of the world. The Githzerai oppose the Githyanki, so operatives would obviously wish to keep the artifact out of Githyanki hands.

That issue of Dungeon was #100. The adventure was called "The Lich-Queen's Beloved" and was all about the skies filling with Red Dragons and airships. It was for 18th level characters and was designed as the ending to the Incursion campaign.

I don't know of any online source, at least not legal, for the Factotum. It's not Open Game content.