Tetrisoids are a species with a spherical central body and four equidistantly placed arms, each ending in a three-fingered "hand". They generally walk on three arms while manipulating objects with their fourth, but their unique body configuration does not allow them to perform many of the basic tasks that humanoid species take for granted (such as lying down or sitting).
An unnamed Tetrisoid is often seen among the ranks of Tagon's Toughs.