An insectoid sentient species, Mustafarians were noted to be hardy and well adapted to survive their homeworld of Mustafar’s extreme temperatures. Both subspecies had distinct roles in society as well as differing physical attributes, with Northern Mustafarians being of a taller build and reaching heights of roughly 2.3 meters, while the shorter and stronger Southern Mustafarians often reached heights of 1.5 meters. Northerners had less resistance to high temperatures than their Southern brethren, whose tough skin could better resist heat. Both forms of Mustafarians had blaster-resistant skin, but they still needed armor to protect themselves while working around lava as it was very dangerous. Some Mustafarian clan leaders were known to be able to manipulate lava using the Force.

Mustafarians lived in underground caves created by Mustafar’s native lava fleas as they ate through the planet’s crust. Living mostly in underground buildings designed in the shape of kahel cave fungus, most of their species only ventured to the surface in order to mine the valuable minerals from the lava flows, or for a coming-of-age ritual in which a young Mustafarian must saddle up on a lava flea and leap over a raging lava stream without any protective clothing. Northern Mustafarians often became guards and expert lava flea riders, while Southern Mustafarians handled all heavy labor, although they could too ride lava fleas. Members of the Mustafarian species spoke an insectoid, buzzing language of the same name.

Mustafarians often fashioned armor from the heat-resistant shells of lava fleas and wore breath masks while working near lava, which made them appear mysterious and uniform to outsiders. Floating on heat-shielded craft, many Southern Mustafarians on the surface wore this protective armor in order to scoop lava into giant cauldrons attached to metal rods, which could be carried away by DLC-13 mining droids.