Xōl'uu (R.il'a IV) is the fourth planet from the sun of the R.il'a system, Xi'an Empire (SaoXy'an). Originally terraformed and developed as a planet to train military ground forces and build weapons, it was reclassified as an industrial world by the Xi'an government at the conclusion of the Xi'an-Human Cold War. Its military factories have been decommissioned and replaced with commercial manufacturing centers, and its strategy centers have become office buildings.
In the early 2900s SEY, the Xi'an government established a policy of offering real estate discounts to United Empire of Earth (UEE) businesses that established branches on Xōl'uu in an effort to facilitate easy trading between the Xi'an Empire and the UEE.