Soul Drinkers (Legiones Astartes)

One of a new generation of Astartes, the Soul Drinkers were not founded to replaced one of the fallen legions, but instead to take up arms against the enemies of the Imperium in the Second Great Crusade. It is not known which of the original Legions they descend from, and although they have their own beliefs, they chose not to share them with outsiders. Despite this mysterious heritage, it has not stopped them from contributing to the creation of the Pax Imperialis Secundus. From their impressive collection of ships, they have scoured a thousand alien fleets, boarding them and eliminating all aboard in expert manner and precision. Not deterred by open combat, they are masters of drop pod assaults, landing behind enemy formations and fortifications and tearing them asunder.
Despite their successes and noble efforts, the Soul Drinkers harbor a dark secret, one which if revealed, could spell their doom. Around the beginning of the 34th Millennium, the Soul Drinkers, numbering easily over one hundred thousand, was split in half. The captain of First Company, Nikasios, held the belief that it would be beneficial to construct planet-based fortresses to stockpile equipment and men for their crusades, something directly contradictory to the ideals of the Legion. After his idea was rejected by Legion Master Abelus Cyricus, Nikasios became violent and lashed out at Cyricus, and in his defense struck down his friend and comrade. Despite attempting to hide the deed, it eventually came to life and those Marines who followed Nikasios viewed this as a censorship of their beliefs. Believing themselves at threat, Theophanes, Captain of the Second Company, led roughly half of the Legion into open rebellion. The Legion was ravaged, with countless Astartes killed and numerous ships stolen by the rebels, who then proceeded to flee to parts unknown.