Evarrians were large insectoid predators that averaged four meters in length when fully grown. They were multi-legged with segmented bodies that helped them move rapidly through the mud and water of the Jagomir swamps. Evarrians had excellent eyesight thanks to their many faceted eyes. They were covered in a hard carapace and had two, long, sharp claws protruding from their upper body that were covered with a toxic venom. The venom not only paralyzed the prey, but it also caused a breakdown of the internal organs. Humans were extremely susceptible to this toxin.
Evarrians lived in nests, led by a queen, who would spawn four to six new eggs each year. Once hatched, the larval Evarrians join the rest of the nest. The larvae were more vulnerable to attack until their crimson carapace hardened upon maturity, though as a defense, their venom was also more concentrated until their claws fully hardened.
When the Rebel Alliance relocated to Jagomir after the destruction of their base on Arda I, the construction of their new Resolute Base caused much of the Evarrian's natural prey to be driven away. The desire to protect their nest, combined with their growing hunger, caused a local nest of the creatures to becoming increasingly aggressive and hostile. After a Rebel scouting party was attacked, a group of individuals was given the task of investigating and eliminating the Evarrian threat.
- Onslaught at Arda I (First appearance)