VAGUE IDEA ALERT!
This is definitely not fleshed-out very fully. I have all kinds of ideas for the setting, but most center on the stories of Tora the Ronin, who by the time of this setting is a known hero. So I'll work on it, but don't expect great things. Or perhaps I'll just use this as a place to put down my ideas.
My main ideas for this setting-
-A vast sandy desert, believed by its inhabitants to be endless.
This desert, often called the Big Sand or the Great Desert, is home to tribes of wild Scavengers (also called Desertfolk, Sandpeople, Sand Rats, Sand Bastards) who dress in long water-cloaks, carry around heavy water-retainers and other machinery, have rifles, and ride huge lizards and sandbikes (imagine a combination of Harley-Davidson motorcycle and Star Wars swoop bike and you've got it). Think of mixed Fremen, Hell's Angels, barbarians from Mad Max, rolled into an anime-influenced package, and that's what I'm thinking of.
Also dwelling in the desert, in addition to Scavengers and various small animals, there are the fearful Sandgorgons, huge sandworm-ish monsters. Sandgorgons are powerful foes, and no man has ever defeated one single-handedly (except for Tora the Ronin, but he's more than a man).
-Somewhere in the desert, there is the Water-Rift, a huge crater-like pit in the desert where water pours from the walls and into a lake at the center. Around the edges grow jungle, and in the shadow of the cliff wall, there is the city of Water-andu, a huge metropolis ruled by the Daimyo, a mysterious being who always goes masked and claims to own all the water in the Water-Rift. The Daimyo is served by the Joubu, samurai-ish warriors (of which Tora the Ronin was one). The culture of the Water-Rift is parts Arabic, parts Japanese.
Water-andu (and the Water-Rift) is the only significant source of water in the Big Sand besides fastpools (oases which appear and disappear within three days). It is frequently raided by the Scavengers.
-Throughout the desert (generally close to the Water-Rift) there are small, walled towns (imagine an Arabic desert town, or the town from Stargate) called Soft Towns by Scavengers or Tribute Towns by the Daimyo of the Water-Rift, which depend on water-shipments from Water-andu for their wellbeing, as well as trade amongst themselves and with Water-andu. Some are mere villages, while others are small cities. Some Tribute Towns have their own Joubu to defend themselves against Scavengers and Sandgorgons.
-There are two religions- the Conqueror God (called most frequently Ashoka, but also Xerxes, Charlemagne, Caesar, Ascar, and other things), god of warriors and strength (popular for Scavengers, Joubu), and Ji-Erunamu, the Lord of Heaven, whose corrupt priesthood rules parts of the Tributary Towns and whose half-machine warriors forcibly convert entire regions. The Conqueror God's religion is disparate, while the priesthood of Ji-Erunamu is led from the great machine-city of Meru, named for the holy mountain Meru (the only mountain in the Big Sand) upon which it sits.
(In truth, Ji-Erunamu is a gigantic machine, and Meru is merely the smallest portion of its parts, which fill all of Mount Meru)
-The Earthblood Warrens are a group of underground cities built along lava tunnels. The Earthbloodmen rule them, and ride huge lava-serpents and such.
-The Keigai Waste Zone is a huge section of the Big Sand which is absolutely clogged with ancient things- giant piles of scrap, crumbling remnants of structures, huge mountains of trash... Basically, take a landfill and add to it the remnants of a dead civilization, extend it to the size of the state of California, and put it in the Sahara Desert.
-The desert is filled with signs of ancient civilizations which most people totally ignore- giant rusting robots, walls of sculptured masonry half-buried in sand, piles of shattered statues, the hulks of huge metal buildings, et cetera...
-Most of the people of the Big Sand (and the Water-Rift, and the Tribute Towns, and Meru) have epicanthic folds in their eyes (Asian eyes) but are otherwise wildly differentiated in appearance.