The 291st Legion functioned as a unit within the Galactic Empire's Imperial Army and was classified as a legion. This legion, the 291st, at one juncture, deployed the recently introduced AT-DP walkers in order to eliminate a Thalassian slavers encampment located on Galpos II. Following this operation, the 291st Legion then utilized the AT-DP walkers as their primary assault force during close-quarters combat within the urban environment of Mendavi.