We've played two sessions in a prehistoric game. We wanted to make a little "vanilla prehistoric setting", with dinosaurs and stuff like that, not very serious, to play one-shot adventures when DMs couldn't progress in bigger campaigns.
There was quite a lot of interesting ideas.
I'm copying it here:
There are three primordial gods : Azd, the day, that which is , the present time; Nocte, the night, that which was and that which will be, futur and past ; the unnamed, that which can't be and must not be. Azd and Nocte created the world, and Azd fought a long war against the unnammed. The three are neutral.
Azd and Nocte created four gods : Gaia, the earth mother, who will give life to all living creatures. She is CN in alignment, young and impetuous. Ouranos (don't know the english writing), the sky above Gaia, who will bring direction and order for all living creature. He is LN in alignment, sage and farsighted, but somewhat authoritarian. Nai-Chton was created to fight the Unnamed. Thanks to his prowess, the Unnamed was banished, but Nai-Chton suffered from backfire and is now corrupted and evil. Heoma was created to bring hopes and
dreams to all living creatures. She is NG in alignment.
(they are overgods (Gaïa and Ouranos) or powerful greater gods (Heoma and Nai-chton)
The creation process continued : The Gaïan spirit were created by Gaïa alone, to be her servitor. They have the form of animal and are revered by the various tribes as totem. They are spiritual guides. (They rank from hero-deity to intermediate god).
The Celestial Children are born from Gaïa and Ouranos. They are just that : Children with godly power. Imagine Zeus, Thor or Venus in diaper. They already have portfolio and clerics, but lack some sense of responsability...
The Titans have been created by Ouranos to watch over the Celestial Children, and protect them from harm.
The Dark Spirits are Gaïan Spirits, corrupted by Nai-Chton. They live only to propagate evil and terrors.
Planes: The Prime Material Plane is the home of Gaïa. It is a finished plane.
It is coterminous and coexistant with the Plane of Spirit, which is the plane of Ouranos. You can reach it either by the Ethereal Plane (which act as a border where the spirit plane and the material plane overlaps), or by flying high enough in the sky.
The Celestial Children have their realms in many demi-planes in the Plane of Spirit.
The Faerie plane is hidden within the deep ethereal, and is the realm of Heoma. It is sometime coexistant with the prime material plane, because the ethereal is not a stable place. You can reach it through dreams, ethereal travel or occasional gate in the Prime.
The Elemental Planes are coterminous with the prime. (or they aren't : how large must be a gate between two plane for saying that they are coterminous ? Anyway, to reach the plane of fire, look for volcanoes...)
The plane of Shadow is the body of Nocte, just as the earth is the body of Gaïa. You cab reach it through dark places, and magic. Here hide Nai-Chton. He has created some demi-plane here, who are the realms of the Dark Spirits.
The Far Realm is the place where the Unnamed has been banished.
I don't know where to put Azd. Perhaps in the prime material, as he is the Sun, perhaps in the Plane of Spirits. If so, Ouranos will likely be in the sky border betwen the Prime and the Plane of Spirits.
People:
In such world, each race has a place, and a goal.
The Gardians : they have a central role. They must keep the harmony between Gaïa and Ouranos, and fight the force of the Unnamed (now, those of Nai-Chton). Long time ago, the old men(neanderthal), called trusks, were created to be the Gardians. But, they failed, victim of Nai-Chton's trichery, and thus were created the men (Cro-Magnon), called Uitans. Alas, these last often think that eradicating their predecessor is part of their duty. Anyway, Azd do not intend to create another reimplacement.
The Gaïans : Elves and Gnomes were created by Gaïa as servitors, protectors, and playtools. Gnomes are more servitors and day to day protectors, with many affinities with animal and plants (think to forest gnomes); while elves are more playtools and emergency fighters (because of their magical powers : they have an innate predisposition for sorcery).
The Ouranians : Dwarves were created by Ouranos to be his servitors and his apprentices. He gives the steel of the meteor and the secret of the runes. They lives in the highest mountain, ride on griffon back, and are the most advanced of all the races. The halflings are the messengers of Ouranos. They are nomadic, riding giant foxes or other animals, exchanging goods with the various tribes, and bringing news to all. While the dwarves are somewhat secretive, they are not. They are often seen as secret's thiefs, and thus not always welcome.
The Fallen : Hobgoblins have received dark blessings from Nai-Chton. They have built cities and longboats, they practice foul sorcery, and are the most feared slavers. They are the more organized of all the races, and none but the orcs are more cruel. The Orcs are quite the opposite : bestial, chaotic, more barbaric than any human tribes. They eat animal meat only if they don't have anybody else to put under their yellow teeth. They rarely take prisoners, and those do not survive more than a few day. Half-Orc born of human mother do not exist.