Legion Master

A Legion Master (sometimes known as a Lord Commander), was a title granted to the commander of one of the Legiones Astartes during the early years of the Great Crusade. Originally, this post was held by an ordinary Space Marine Legionary in the absence of their missing Primarchs, who had been mysteriously spirited away from the Emperor's gene-labs by the Ruinous Powers. In their absence, command of a Space Marine Legion was given to a select few - warriors who were chosen for their tactical acumen, steadfast dedication and loyalty to the Emperor of Mankind and His Great Crusade as well as their unmatched personal combat prowess. Prior to the rediscovery of the Primarchs, they were the highest echelon attainable within a Space Marine Legion. As the Great Crusade progressed and the missing Primarchs were eventually found, these gene-sires would then assume command of their respective legions, replacing the Legion Master as overall commander.

List of Notable Chapter Masters
The following is a list of all known Legion Masters that commanded one of the Space Marine Legions: