The Space Wolves (also Sky Warriors of Russ, Rout or Vlka Fenryka or Wolves of Fenris in Fenrisian) were the VI Legion of the twenty Space Marine Legions. Their primarch is Leman Russ, and during the Great Crusade they gained a reputation as the Emperor’s executioners and instruments of punishment. After the Horus Heresy and the resultant reforms, the legion was divided, its first and only time, into two chapters: the new Space Wolves chapter retained the name of their parent Legion, while the second chapter took on the name of the Wolf Brothers. The latter however suffered from mutation and was disbanded. It is currently unknown if there are any other descendant chapters of the Space Wolves at all.
The Space Wolves are notorious throughout the rest of the Imperium for their ferocity in battle and their defiance of authority, including the dictates of the Codex Astartes that govern the organization and combat doctrines of other Space Marine chapters. They are generally considered the greatest warriors of the loyalist Astartes Chapters.