Tanzrobi is a First Generation world, having been seeded by the Galen about 500 B.C. with Bantu people from Africa. The Tanzrobians, also known as Azizi, were futzed the the Galen, who engineered them into seven septs of increasing strength and invulnerability: akwanza, apili, atatu, anne, atano, asita and asaba.
Tanzrobians were organized into tribes, each of one sept, except for the asaba, who served as guardians and judges to the others. They led a deliberately pastoral and nomadic existence, much like that in Africa, for most of their history; but trade with the Scalantrans supplied them with technological benefits llke computers and comlinks and medicines for themselves and their cattle. Besides exotic handicrafts, they exported maleca -- mercenary soldiers, known elsewhere as alecans, and drawn from those in the lower septs disaffected with the Rousselian culture. But most Tanrobians were happy with their life, and considered themselves especially favored by the Galen, whom they imagined watched over them from the clouds.
All that changed in 1479, when the Arion Empire attacked with nuclear weapons that vaporized communities and GARs that killed even the asaba. It was the first invasion ever of a First Generation world by the Arions, and was to have serious consequences in Galactic history. A few Tanzrobians escaped with the aid of a Scalantran ship, and there were occasional escapes after that. But most were rounded and forced to live in towns governed by Arion commanders. Over the centuries, some Tanzrobians came to embrace their rulers, and even served with Imperial forces. There was also occasional cross-breeding between the two races, and even experiments in the creation of hybrid Tset'lars -- which, it was hoped, would escape detection by the Galen.