Thri-Kreen are race of sentient, humanoid insects native to Athas. Thri-Kreen have four arms, though the bottom two are only secondary.
They live in a brood society, ever bonded to the others who hatch from the same clutch. It’s rumoured that they can even telepathically communicate with others of the same brood.
They have their own language which, unlike other languages, is impossible to replicate without a set of mandibles. Their written script is somewhat easier, though there are not many non Thri-Kreen that understand it or can write it.