Arkash Hakkon is the current High Executioner (Chapter Master) of the infamous Executioners Space Marine Chapter. Although he possesses ultimate authority over his Astartes, he must also heed his Company Captains (treated as warlords in their own right by the Chapter's traditions), who along with the Chapter's Chief Librarian, Master of the Forge and Lord Speaker of the Dead, form a war council which by ancient right may, by unanimous assent, overthrow the High Executioner should he prove unfit or unworthy in their eyes.
Unlike the traditions of most Space Marine Chapters, leadership contests for the command of the Executioners can be bloody affairs; with each of the Company Captains having the right to challenge for the title of High Executioner in trial by combat should they so wish. Hakkon more than likely ascended to this esteemed rank through this ritual combat.
In battle, Hakkon wields the Lifetaker; a massive black-bladed Power Axe of archaic design, carried by successive High Executioners as a badge of their office. In 904.M41, Arkash Hakkon entrusted the Lifetaker to High Chaplain Thulsa Kane to signify his leadership of the Executioners during the dark days of the Badab War. To honour the ancient blood debt between the Executioners and the Astral Claws Chapter, the Executioners came to the aid of the Tyrant of Badab's cause in payment to this debt. But they did so on their own terms, much to the Tyrant's frustration.
Operating as an elusive raiding force that struck at the Loyalist's lines across the length and breadth of the Maelstrom Zone, the Executioners remained a persistent thorn in the side of the Loyalists and a force perhaps able to turn the tide of the war, yet seemingly unwilling to do more than give battle against targets of their own choosing, seeking glory and victory, rather than fulfilling the Tyrant's strategic goals. Of all those caught up in the Secessionists' cause, the Executioners Chapter perhaps endured the least scathed and the least tainted.
They had fought honourably and had lived and died by their oaths. In punishment the Chapter was forced to give up reparations and exiled from their home system for the span of a hundred years, in which time they would undertake a penitent crusade to atone for the Loyalist blood they had spilled and be forbidden from taking up new initiates.
- Imperial Armour Volume Nine - The Badab War - Part One, pp. 24, 40-41