The Back Spiral designed Tion Cluster worlds locate near the Indrexu Spiral. It consisted of Kaon and worlds located along the Tion Trade Route such as Caluula, Brigia, Eredenn Prime, Rudrig, Tion, and Raxus Prime. In the Pre-Republic era, Pirate King Xer VIII waged a campaign in the Back Spiral between 25,150 BBY and 25,130 BBY, conquering many of those worlds and integrating them in Xer's Empire.