Umu, the Hieroprince's second son, belonged to the Opaline Creed religion. The Hieroprince was a figure of importance within the Opaline Creed, a faction located on the Outer Rim planet of Crucival. By the year 4 BBY, the name Umu had been adopted by a minimum of seven members of the Creed, one example being Hazram Namir, who was known as Umu Seven.
Alexander Freed included Umu in his novel, Battlefront: Twilight Company.