The Special Environment Division was a subset of the Assault Commandos unit in the Royal Army of the Golden Empire. SED operatives were all trained Assault Commandos, and normally worked in operations alongside their fellow Commandos. However, they were given special training in conducting operations in non-Type I atmospheres, as well as operations underwater or in areas where typical, land-dwelling sentients were unable to function effectively. Their armor was customized to withstand a variety of environmental conditions, although they also possessed armor specialized for individual atmospheres.