The Vek-Rhra Tsenu or Tribals as they are commonly called, are the descendants of the various indigenous people of the Zhu empire. Before the prophet Zhu Shang formed the empire, the Vek-Rhra were scattered tribes living in the various lands touched by the Sea of Chi. Each was different but they all shared a few cultural themes and gave the sea of chi religious focus. They mostly lived in small settlements dotting the landscape while some lived more nomadic life styles. While they all traced common ancestry they each were their own tribes with separate customs and beliefs. They lived in such ways for countless generations until eventually the prophet Zhu Shang came and led the various peoples to victory over the Dark Ones and their outsider armies. Following her example and the power she displayed most of the population quickly converted to her teachings and started to form the Zhu Empire, with various regions becoming kingdoms led by the lesser prophets. As the empire absorbed more and more of the Vek-Rhra, some rejected the idea and refused to be part of some new system.
While the Zhu people weren't happy about it, Zhu herself accepted their decision and reached an agreement with all who didn't want to be part of her new society. They would be allowed to continue their life style without persecution within the vast areas of wilderness that she sought to preserve and keep off limits for development. It was a deal that would last for all time, the tribals would be guarded from outset threats and allowed immunity from imperial law as long as they didn't interfere with things outside of the the designated lands.
As countless generations went by the two groups and the races within them began to drift apart as their cultures became more and more different and they even began to look different. Eventually the imperial Zhu began to resent the Tribals, seeing them as in the way and many seeing them as treacherous heathens instead of as sisters. The ancient decree was clear however so they couldn't outright get rid of their neighbors in the wilderness, instead they became much more proactive and strict about splitting up tribes that get to large. They increased restrictions on tribal traders entering imperial grounds and stopped the old programs of allowing Qigekki of tribal descent to be tutored in their cultures ways, as well as the old deals to get said Qigekki. Ri-kougar and rebel factions began to make hideouts in the same areas as them further increased imperial aggression as well as cause the general public to become more distrustful. In the modern day tribal communities tend to fear and distrust the empire, and there have been a handful of violent incidents in the past few decades. Even the tribals who move into imperial society tend to face a degree of discrimination when in the cities.