Dark Sun - Ruined World
The world of Dark sun is the world of Athas, a barren, desert world destroyed by powerful mages eons ago.
Metal and water are scarce, weapons are mainly forged from stone or bones.
The magic in the world has been altered in such a way that all spellcasters are either considered Defilers of Preservers.
A mage who is a defiler basically rapes the land for more magic power. Every time he is casting a spell he is in a small way destroying the planet.
A preserver is a like a sage or druid who tries to restore life to Athas.
There are slaves, and barbarians, and racism towards many of the ‘lesser’ races. The people of the lands are mostly assholes. Gladiatorial arenas where people fight each other to the death are extremely common.
Athas is ruled by powerful Dragon Kings who are mages with unmeasurable power that essentially are gods to the world.