Leman Russ, also known as the "Wolf King" and the "Great Wolf" during his lifetime, is the currently missing Primarch of the Space Wolves Chapter of Space Marines.

He led the Space Wolves Space Marine Legion during the Great Crusade and the Horus Heresy and is famed in Imperial history for his hatred of psychic powers and sorcery, whose use in battle he viewed as dishonourable and unworthy of true warriors.

After receiving a disturbing vision in 211.M31, Leman Russ disappeared with the warriors of his Varagyr bodyguard, his destination and fate unknown.

Russ, along with his brother Primarchs Angron and Vulkan, were considered to be the greatest warriors one-on-one amongst the Primarchs. Known for his fierce and sometimes barbaric personality, Leman Russ considered himself the Emperor of Mankind's most loyal son and executioner.

He viewed his role as unquestionably carrying out the punishments requited by the Master of Mankind. Among the forces of Chaos he was known as "the Brawler."

Some recent rumours claim that it is Leman Russ who is the unknown force behind the return of the Space Wolves' 13th Company to realspace after 10,000 Terran years fighting the forces of Chaos in the Warp during the 13th Black Crusade of 999.M41.

Several main battle tank variants used by the Astra Militarum have been named after him. The Leman Russ tank is the most prominent, and several sub-variants of that pattern of tank also exist in widespread use in the Imperium of Man, such as the Leman Russ Demolisher.