Stretches of steep mountains separate this harsh desert from the rest of the continent. Rain comes only in the summer monsoon season. Winters, especially near the mountains, are dry and cold at night, characteristic of the high desert. The earth is hard and agriculture is difficult; the societies are hunter-gatherers with sustenance economies. The people have darkened skin but fairer hair than the native Cassilian stock. (Sivans call these people night-heads, and the Azassians fire-heads.) They also have extensive birthmarks which they usually embellish with tattoos to form symbolic patterns.
The Sivan tribes are more tightly knit than the Azassian clans, more scattered than the Cassilian villages. The society is more matriarchal than in other countries; division of labor by sex is the norm but there are exceptions. There is little contact between clans except at the annual Rain Gathering.
The Rain Gathering takes place in late summer, when all the clans gather at the coast. There are contests in hunting, fighting, singing, dancing, and the final rain prayers. Marriages are arranged at this gathering, in line with the fertility symbolism.
Siva remained largely untouched until the early days of Nanianism. The early Cassilian missionaries attempted to convert the Sivan tribes but were shunned, without conflict. These early missionaries preserved the spirit of the religion, which was to suppress science. Since the Sivans had no formal science, they did not need converting. The early Nanians were also mystics, and respected the animism of Sivan religion.
When Dabion institutionalized Nanianism as the state religion, the missionary movement became more violent. Dabion began to send missionaries into Siva in 542. The Sivans were unprepared for the violence of the Dabionian missionaries. A few rare incidents of violence with the Sivans were recorded, and this conflict escalated to retribution.
Dabion recruited troops from Azassi to fight the Sivans, beginning in 546. The long and bloody struggle ended in stalemate. Prophets in Nanian houses in Azassi and Sivan shamans simultaneously pled for an end to the wars, culminating with the Great Prophecy in 553. Dabionian leaders were finally convinced to abandon the conversion mission when Manderan tradesmen argued that the land was devoid of material resources (which allowed Mandera a monopoly on the human resources in the Labor Project).
Some Azassians were stranded after the wars and remained in Siva as nomads, continuing to fight the native Sivans periodically, until they encountered Sivans who had returned from the Labor Project.
Siva was slow to recover from the wars. The population had suffered greatly and the land was not suited to quick growth. When Manderan tradesmen arrived in 623 with food, animals, and other gifts, many Sivans were more than willing to contract themselves (or sell others) as laborers. The Labor Project became known for maltreatment, though, when Sivans sent to work in Karrim and Mandera abandoned their positions and returned to Siva (from the "Outside"). Slaves continued to be abducted as late as the 700s, for use in Marlind, but the process grew more brutal. Animals were also stolen from Siva during the early 700s, especially tigers and log'e, and these animals and people were shown in zoos and circuses.
Many of the Sivans who returned from the Outside were not accepted by the natives, having forgotten or lost track of their clans. These estranged people fought with the stranded Azassians, until they began to cohabitate and intermarry, both being displaced cultures. The nomads took prisoners from the clans of Siva and the Outsiders who occasionally entered still (especially Dabionian peacekeepers). Little was done with these prisoners; the nomads gained symbolic vengeance against those who tormented and enslaved them.