He was one of the Astral Claws who survived the Loyalist Astartes' final assault on Badab Primaris during the closing days of the conflict.
Garreon was the Chief Apothecary and one of the Veteran Battle-Brothers of the former Astral Claws Chapter. All Apothecaries of the Adeptus Astartes had heard of Garreon in the years before the Badab War. His research scrolls and early documentation were lauded for their extraordinary insight and understanding of Space Marine physiology, and many Apothecaries had studied Garreon's earlier works.
The idea of meeting such a legendary figure might once have filled an Apothecary with interest and reverence, but now it fills them with nothing but revulsion because of Garreon's corruption and betrayal of the Emperor.
As the Badab War unfolded, the sins and malice of the Tyrant of Badab soon became clear for his enemies to see. One dark development on the battlefield was the arrival of the Apothecary Vivisectors, or "corpse takers" as they were known by the human Auxilia of the Tyrant's Legion. They were created at the suggestion of Garreon in order to recover the gene-seed not only of their fallen brethren, but of any Space Marine who had fallen on the battlefield.
In the case of the enemy, they would perform this blasphemous perversion of the duties of a normal Apothecary whether their subject was living or dead. With this gene-seed, Huron intended to secure the Astral Claws continued increase in numbers and eventual victory over the Loyalists by raising a force similar in size to the ancient Space Marine Legions. To the Loyalist Space Marine forces facing the Renegades there could be no greater insult or more hateful crime than taking the gene-seed of another Chapter.
During the final Loyalist assault upon Badab Primaris, Garreon was one of the few Veteran Battle-Brothers who survived, breaking through the Imperial cordon and fleeing towards the relative safety of the Maelstrom.
The Red Corsairs call Chief Apothecary Garreon "The Corpsemaster," not because he harboured any desire to see the dead walk, but because he took a pathological interest in the biology of the dying and the dead among the Astartes, both of whom provided him with a harvest of precious gene-seed.
He believed, as had many Apothecaries throughout the history of the Adeptus Astartes, that the future of their brotherhood lay in a better understanding of human genetics and xenobiology.
He performed regular dissections on enemy Space Marines and his fellow Red Corsairs both -- in some cases whilst his subjects were still living. He could keep his victims alive for a phenomenal length of time, reducing them to skeletal, still-living things that begged for a release that was an eternity in coming.
Garreon was tall even for an Astartes but possessed a leanness that would have made him seem thin had he not been a Space Marine. Sharp, angular cheekbones stood out prominently in a scarred face whose most striking feature was the eyes.
An impassive, unreadable dark brown, the colour of Garreon's irises were so dark that his pupils were barely visible. His hair was a tawny brown mane that fell to his shoulders, streaked through with grey that hinted at his advancing years.
It was a face that was filled with great intelligence but also underlined with the terrible cruelty born of a hunger for forbidden knowledge.
- Imperial Armour Volume Nine - The Badab War - Part One, pg. 184
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