Ahriman, whose full name is Ahzek Ahriman, is a Chaos Space Marine and the most powerful Chaos Sorcerer of the Thousand Sons Traitor Legion after their Daemon Primarch Magnus the Red himself. Ahzek Ahriman was once the Chief Librarian and first captain of the ancient Thousand Sons Legion.
Ahriman has always sought to better comprehend the nature of his patron Chaos God Tzeentch and of the force of Chaos itself and gain the unrivalled power such knowledge will bring.
His action in crafting the Rubric of Ahriman, perhaps one of the greatest works of sorcery in history, would ultimately result in his banishment from the Legion he had hoped to safeguard. It is his intense need to find a way to undo the effects of the Rubric upon his beloved Thousand Sons that first drove Ahriman on his quest to seek out the deepest knowledge of Chaos. He remains a wanderer across the galaxy, forever searching for any knowledge that will allow him to finally grasp the greatest of all enigmas in the universe — the true nature of Tzeentch himself.