The roi were a race of nomads that lived and traveled around the northern part of the southern continent. Croaker the Annalist recorded little about them, but mentioned they are skilled horse riders. In his youth, he learned some of their language, so they presumably ranged at least as far north as Padora, Croaker's birth city.
During the Black Company's march south in Shadow Games, four professional caravan guards deserted from the roi, including Shadid and Patience, and joined the Company. The roi were assigned to help Otto and Hagop create the new cavalry force of Taglios, once the Company was hired by the Taglian prince, the Prahbrindrah Drah, and his sister, the Radisha Drah. Croaker wrote that he could depend on "the bloodyminded roi to kick ass where that was needed" and admired their newly-formed cavalry. Without the support of the roi, Croaker wrote that Otto and Hagop's cavalry "would have been a travelling circus".
The fate of the four roi members of the Black Company is uncertain. The roi are not mentioned in the Annals after Shadow Games, neither as a group nor as individuals. This could suggest they did not survive the defeat at the Battle of Dejagore, or the subsequent bloody Siege of Dejagore.