The primary civilizations of this world are gathered around the huge central sea. And while the other sea is just as expansive, its surrounding shorelines are wild and relatively unexplored. The Inner Sea’s human civilizations are at odds with each other and are at the Bronze Age of development.
Halflings and orcs live alongside humanity while elves, dwarves, and gnomes have their own, older, kingdoms in the deep forests, expansive mountain ranges, and deep valleys in the more trackless parts of the world. The elves use wooden and bronze armor and weaponry with some additional silver items while the dwarves use stone and bronze armor and weaponry with some additional iron items. The gnomes prefer to use wood and stone; they have a more primitive way of life.
True steel on this world is a rarity.
There are goblinoids, kobolds, and lizardfolk* as well, and, in fact, any creature described in the AD&D 2E Monstrous Manual has a place on this world. It should be noted, however, that the demihuman subraces are very rare on this world. Also, half-elves are uncommon and half-orcs are rare. There is less animosity towards half-elves and half-orcs, which has to do with the history of the planet.
The legends of the world state that there was a First World that gave birth to this Second World. The First World was a place of advanced mechanisms and powerful arcana. It destroyed itself eons ago. The world nearly died. Its races suffered through a second Stone Age. Nature took back the planet and all the civilizations of the First World were washed away by rising flood waters, buried by earthquakes and landslides, or overgrown by the greenery that now covers most of the world.
The races, initially, were forced to band together to survive. As time marched on, the world’s various peoples either went their separate ways or remained closely united. Regardless, each race passed down its stories of cooperation and respect for the other races of the world. And while some of these tales have been lost to the eons, the stories of the dwarves, elves, and gnomes have survived pretty much intact to this day. The written stories of the humans, halflings, and orcs have become a mixture of the three races original tales.
All of the core classes from the AD&D 2E Player’s Handbook are available for this world. Character kits are also considered core for this setting; however, the kits from the Complete books must be judged on a case by case basis. The historical books, once I reacquire them, will be vital to this world’s development**. Psionics is not a part of this world. Tome of Magic is also a core book for this world, however.
* I’m going to use the 3e monster “folk” names. They sound better to me.
** I do have a few of them such as Age of Heroes.