Khagan

The term Khagan refers to the leaders of the tribes of nomadic peoples in the Pardrayan steppes. It is used on both sides of the Shaum, with the Arshaum and the Khamorth. A khagan who leads the most powerful clan amongst the Khamorth was said to be the Royal Khagan, and his tribe the Royal Clan.

During the War Against the Yezda, the Celtic chieftain Viridovix and the Greek physician Gorgidas, one fleeing the Videssian Emperor's wrath and the latter fleeing the death of his lover, rode with a Videssian embassy to the major Arshaum khagan in the Shaumkil - to persuade him to join the fight against the Yezda]]. Along the way, they witnessed Avshar manipulate the outlaw Varatesh into becoming Royal Khagan and do his will. In fact, they took part in the battle against Varatesh and Avshar.

Historic Parallels
Khagan or qagan was used by Mongolic and Turkic tribes to denote the rank of emperor. It can also roughly translate to 'Khan of Khans', which is equivalent to the Persian King of Kings.