Off the coast in the north, somewhere where the wild, uncharted borders of "north Qizmir" start to become the southernmost Forbidden Lands, deep in the Qashan Jungle, is a large island (about 2/3 the size of Madagascar) that is known only by reputation to the rest of the world as Cannibal Island. To its natives, however, it's known as Kanem Sennar. The natives are human, it's presumed, but differ radically in appearance and habits from the rest of the peoples in the area. Those few who actually recognize them fear it is corruption from the Forbidden Lands that has caused them to become so dangerous.
Kanem Sennar is a land filled with monolithic yet abandoned architecture; massive megalithic abandoned temple complexes dot the jungles and are somewhat frequently encountered, but the natives see them as sacred and avoid them. Despite the great heat and frequent sunlight, the natives of Cannnibal Isle are pale-skinned; with an almost chalky grayish white complection that resists tanning and sunburn both. They tend to have raspy voices, occasionally exhibit complete hairlessness (with the exception of eyelashes) and file their teeth to sharklike points. Their eyes are often strikingly pale blue or green or gray, their hair is either jet black or pure white (regardless of age) and because of their strange cults, they often have black markings painted on their skin which give them the appearance of stylized human skeletons. They lack a strong state structure, being organized into clans and cults which routinely raid each other for slaves, women, goods, and heads, and they practice frequent ritual cannibalism (hence the name of the island.) In fact, the Sennarite natives have a weakness; a genetic tendency to devolve into ghoulism; a state where sentience fades, the body mutates, and they become almost feral, anthropophagic monsters, haunting the darkened ruins and jungles and dragging unwary prey off to become their next feasts.
The Sennarites are not savages, though, and mercenaries and assassins sometimes make their way into the "civilized" parts of the world. They find that their metallurgical and industrial capability, in a cottage industry type of fashion, are the equivalent to anything happening in Terrasa, Baal Hamazi, Qizmir, etc.
Sennarites are still extremely exotic, and few people have seen them, or seeing them, would recognize them as the legendary inhabitants of equally legendary Cannibal Isle, but from time to time, they can be found throughout the region. When they do, they use the rules for any other human; the differences between Sennarites and, say, Terrasans are cosmetic and cultural only.