==The Thirteenth Company==

''See main article: [[13th Great Company]]''

Space Wolf legend states that the group that came to be known as Thirteenth Company was sent by Leman Russ to pursue the [[Thousand Sons]] legion, after the failed attempt to eliminate the Chaos-supporting legion. They vanished from Imperial records, and their loss is honoured by a black stone in the Grand Annulus (the record of Space Wolf Great Companies).