Eastern Rayana Savannah
First understand that the Rayana Savannah is Big. Very big. It is larger even than the massive Yaku Plains. It could take weeks of travel just to cross it. Even when someone does attempt this, the wicked Hyena Katanga and Manscorpions have their tribes and villages somewhere out there, and they are very territorial. Wemics and other creatures also inhabit the plains, so the area has become taboo for most races. It is too dry for lizardfolk, snake or caiman katanga, too open for saru, pangolin katanga or monkey katanga, and too big to cross safely for the butu, korbokuru, or shu. The tiger katanga are frequently chased away by the Simbara tribe for some reason. In short, the eastern reaches of the savannah are taboo only in that it represents a massive unknown territory. Only a few Wise Ones travel deep in this direction, and that is mostly as an occasional pilgrimage to the well-hidden Elephant Graveyard.