Nureyev is an eternal creature that first entered the current Epoch during the early days of Tharuden. He resided for a long time in Tharuden working with the God-King. He fought for the city of Koreth during the War against the Golden Empire. He was one of The Five that created The Linking Ward as well as the Fortu. When Rhysmaeon looked to be about to betray The Five he created the form of Sigmund to hide in and was subsequently suspended in time for a long period.
In the previous Era Sigmund resurfaced and was involved in many of the momentous events at the end of the fourth Era. It was not until the advent of the fifth Era that Nureyev began to again manifest as himself, this time as an alternate form of Sigmund.
Nureyev appears as a tall and slightly muscular black man somewhere between the inhabitants of Venn and those of Tharuden. Nureyev is bald and has a tonsure of shining red gems that are infixed into his skull. His eyes are black and staring into them you can see motes of light that mirror the universe of the night sky.
Although Nureyev appears human he is something else entirely verging on an Eldar but not being tied to a location as much as one. He normally wears nothing but a loin cloth and this is true whether he is in the hot lands of Tharuden or in the Frozen Wastes.
During his early days studying at the Royal College of Tharuden and acting as an advisor to the God-King, Nureyev would dress as a typical Tharuden Great One. Later in the war against the Golden Empire he was often seen wearing his silver "living armor" and wielding the spear of destiny (one of the forms of his living weapon). In battle Nureyev most often levitated, raining bolts of power down from the tip of his spear, though his involvement in the war was more often working with, or defeating, the great wards rather than as a direct combatant.
It is said that in the Fourth Epoch Nureyev existed as well and was one of the few Builders (Olactalan) to transition to the current Epoch but retain some awareness of his "past". Some even say that his history extends as far back as the Third Epoch (The Questioner/The Betrayer).