Fefze were insect-like beings standing about a meter tall, characterized by their black exoskeletons. Their antennae served as organs for both smelling and hearing. Communication among them involved rubbing and clicking these antennae. In moments of danger, Fefze could withdraw their heads and legs beneath their protective shells. These shells were also capable of splitting open, transforming into two wings that enabled brief flights.
A defining characteristic of the Fefze was their highly adaptable digestive system, capable of breaking down almost any carbon-based organic substance. This process involved coating food with strong digestive acids to release the carbohydrates, which the Fefze then consumed, leaving behind a protein-rich residue. This digestive capability also served as a defense mechanism; they could eject their potent digestive acids to deter predators or simply escape, leaving behind a protein-rich paste as a distraction.
The abundance of food available to the Fefze, coupled with their lack of fine motor skills, hindered their technological advancement and limited their exports.
A solitary Fefze possessed an intelligence level comparable to that of other non-sentient insects. Nonetheless, each Fefze was an integral part of a swarm, typically consisting of ten to one hundred individuals. The brain of each Fefze functioned as a component of a larger, unified intelligence. While an individual Fefze had a lifespan of approximately 10 years, swarms could endure for centuries.
Fefze swarms originated as small clusters of hatchlings from the same egg mass. Swarms expanded their numbers through a ritual known as the swarm dance. During this mating ritual, male Fefze from one swarm would fertilize the eggs of females from another swarm (and vice versa). Each swarm would then transport a portion of the fertilized eggs back to their territory, where the hatchlings would integrate into the existing swarm. An additional egg mass would be abandoned, with the hope that it would evolve into a new swarm. Over time, the Fefze swarm dance evolved into a sophisticated art form.
Fefze swarms gained recognition throughout the galaxy for their skills as dancers, visual artists (specializing in organic and temporary mediums), and even musicians. Certain Fefze swarms were also employed by organizations like the New Horizons Development Corporation as colonists and food producers, due to their ability to convert nearly any material into sustenance for other species.
A Fefze swarm was once hired to work on Duro. Due to the pervasive pollution, they underwent a mutation, transforming into the Fefze beetle, a non-sentient predatory creature. Several swarms—including the affluent and pro-Imperial Nat'xikta swarm—established colonies on the planet Brolsam in the Kathol sector, where they played a role in persuading their Rodian and Human neighbors to align with the New Republic forces.
During the Swarm War, the Fefze were among the sentient insectoid races that became Joiners and sided with the Killiks in the conflict.