The Imperial Viceroys, appointed by the Imperial Sovereign, were important officials in the central government of the Star Imperium.  Their appointment was approved or rejected by the Imperial Parliament.  By tradition, one Viceroy was of the race of Star Elves while the other Viceroy was a member of the race of Asguardian Dwarfs. When the ruling Sovereign was physically or mentally incapacitated or the office was vacant, the Council of Twelve appointed the Viceroys with the approval of Parliament.

After the establishment of the United Planets in Year 13,100, the two positions of Imperial Viceroy are abolished.