The EVO troopers (short for "Environmental") were one of the Empire's most specialized stormtroopers. Equipped with heavy enhanced armor with breathing tubes and went through a special training, they were able to survive in the most hazardous conditions such as extreme heat, acid rivers, and lightning. They were equipped with FA-3 flechette launchers and some utilized T-21 light repeating blasters. EVO troopers could be encountered wherever extreme environmental battlefield conditions existed and several were posted on the science ship ISS Empirical, Kashyyyk, Felucia, Raxus Prime, and even the unfinished Death Star. They were specially trained and equipped with equipment made for harsh conditions. The brunt of them were be picked from groups of stormtroopers who expressed hate to non-humans, which made them more aggressive towards the aliens they encountered on harsh worlds. They were eventually succeeded by Hazard troopers.