The Zwiba

The Zwiba are a race of Humanoid inhabiting the city of Nugwidu, on the coast of Grimgar, far to the south of Vele. They're isolationist and have cut themselves off from the rest of the world since long ago, developing a completely unique culture and language. They're known to be dangerous and extremely aggressive, going as far as attacking any none Zwiba which come to close and eating them if they manage to capture their victim, however a few people did manage to establish friendly contact, Kisaragi being one of them.

According to Yume the Zwiba all look very similar, as such, the Zwiba could be genderless or have very little sexual dimorphism.

Culture
Almost nothing is known about the Zwiba's culture because of one of the main aspect of said culture : xenophobia. The Zwiba are extremely aggressive toward almost anyone else, capturing and eating stranger who approach their territory. They've been this way for a long time, so other races know very little about them, while the Zwiba have developed a culture and language unlike anything else.

From what was seen during Level. 14++, it seems like they have a rather minimalist culture, most of them wearing few clothes and no shoes. Moreover, they don't drink nor sing, they also avoid talking in public, preferring to instead lay motionless on the ground in a state which seems similar to meditation.

One of aspect of their culture which seems quite important are the rods that all of them carry. Those long, thin, lustrous metal rod are tipped by a variety of heads and while we don't really know what purpose they serve, they do seem to be use for ceremonies and could be a status symbol as the individual who seemed to be their chief or representative carries a special colorless transparent rod.

According to Yume, the Zwiba have one of the strangest language she has ever heard.

Biology
The Zwiba are a race of humanoid with grayish rock-like skin in both color and texture, since no comment is made about their size, they're likely human-sized or close to it. Zwiba are particular in many aspects: they have no hairs, 7 digits and toes on each hand/feet, their body is covered in yellow and blue line patterns, and they smell like freshly backed pastries. However, the most peculiar part of their anatomy is probably their jet black eyes, in which golden lines that can be seen in the back, swaying as the eye moves around.

Technology
The Zwiba seem to be technologically behind the main races of Grimgar as they live simple lives, having no form of bedding and few clothes. And more importantly, they're unable to build any vessel bigger than a fishing boat, while others races are able to build boats capable of long oceanic travel.

Trivia

 * Kisaragi theorized that the reason no ships, other than fishing boat, which leave the port of Nugwidu ever return could be because they come from another continent and are trying to go back to it.