"To merely execute warriors who might still bring grief to Mankind's enemies is a waste and a sin!"
A Death Oath is one of the most severe punishments that can be meted out to a Battle-Brother of the Loyalist Space Marine Chapters by his superiors. If a Battle-Brother has been found severely wanting, he will be forced to take an oath of moment to either fulfill a superhuman task or die trying, exiled from his Chapter.
Only if he manages to succeed at this suicidal task and survive will he be allowed to return to his Chapter, for he will be considered to have been absolved of his failures by the Emperor of Mankind Himself.
"The Codex Astartes' ultimate purpose is not to tell us how to be the ultimate Space Marine, Uriel, but how to be a loyal Space Marine. Without having to account for our actions, we Ultramarines would be no different nor better than the traitors of the Black Legion!"
The tradition of the Death Oath has been inherited from the ancient time of the Great Crusade, when both individual Space Marines and entire Space Marine Legions would take solemn oaths of moment to accomplish some glorious goal or die trying. Often, a dishonoured Space Marine would swear an oath of moment to accomplish a task considered nearly impossible even for a superhuman Astartes, and find redemption in death while trying to fulfill the oath. If by a miracle the Astartes managed to accomplish his heroic task, he would then be vindicated, and welcomed back amongst his Battle-Brothers as a hero.
In the late 41st Millennium, a Death Oath is not often pronounced. Space Marines are indoctrinated and psycho-conditioned from the moment they are accepted as Aspirants into their Chapter that to fail the Emperor and their Primarch is the worst sin possible. Yet for all their fearlessness and prowess in battle, failure is not unknown to the Space Marines, and some events simply cannot be ignored or prayed away. The loss of a sacred Chapter relic, or unnecessary losses in battle are but two examples of failure for which a Space Marine will be called to account. In some instances, the Astartes' superior will impose a Death Oath upon the penitent Space Marine. However, the monastic existence of the Astartes, and their fanatic reverence for their Primarch progenitor sometimes calls for punishment even in victory, as was demonstrated by the Death Oath pronounced upon the Ultramarines' Captain Uriel Ventris after his victory over the Tyranids at Tarsis Ultra: to the Ultramarines, achieving victory while disregarding the Codex Astartes is a grievous sin.
When the Death Oath is pronounced, the Battle-Brother will receive his task before the whole of the Chapter and then be cast out. For all intents and purposes, he is dead to his brothers and no longer exists. To receive a Death Oath is a harsh punishment for an Astartes, for he will then be truly alone in a hostile galaxy. Most Astartes who receive such a punishment die trying to fulfill their oath, but a few manage to miraculously succeed and are welcomed back to their Chapter as heroes after being tested for any corruption. A few others, unable to fulfill their objectives, either join the retinue of an Inquisitor or petition for service into the Deathwatch as a Deathwatch Black Shield, in order to give their death a measure of meaning. Sadly, some Astartes lose their sanity completely and turn Renegade, filled with nothing but hatred and contempt for the Imperium they were forced to leave.
Despite their similarities, the Death Oath is not the same as the Warrior's Pilgrimage tradition: the former is an exile from a Space Marine's Chapter enforced as punishment, while the latter is a voluntary exile in order to atone for wrongdoing and eventually return to the Chapter if the quest proves successful. However, the two remain closely linked, since the situations that would prompt either to be enacted upon an Astartes are identical, and it is not unheard of for a Space Marine to request to be allowed to make a Warrior's Pilgrimage from his Chapter Master at the same time his fellows request that the punishment of exile be meted out upon him.
The Sagyar Mazan
The people of Chogoris are possessed of great wisdom and capable of deep compassion, but these characteristics are tempered by a fierce and uncompromising sense of justice that can lead to acts of catastrophic failure being rewarded with death, delivered by the hand of a warrior's superior. Occasionally however, this punishment might be commuted to exile by a merciful leader sympathetic of mitigating circumstances. Amongst the White Scars Chapter, those exiled from their Brotherhood are known as penitents, or the Sagyar Mazan, and it is their fate to seek out an honourable death and in so doing, wash away any stain of dishonour.
Notable Death Oaths
- Captain Leonatos of the Blood Angels - Captain Leonatos lost the Blade Encarmine, a Chapter relic and Master-Crafted Power Sword that had once belonged to the first Chapter Master of the Blood Angels in battle against Orks. The Blood Angels' Chapter Master, Lord Commander Dante, and Chief Librarian Mephiston imposed a Death Oath on Leonatos and the remaining survivors of that fateful battle that required them to either retrieve the Blade Encarmine and bring it back to Baal in victory, or die in the trying.
- Captain Uriel Ventris and Sergeant Pasanius Lysane of the Ultramarines - While defending the planet of Tarsis Ultra against the Tyranids, Captain Ventris assumed command of a Deathwatch Kill-team after its leader was slain, and assisted Inquisitor Kryptman in capturing a Lictor and devising a genetic toxin from its genome with which they could kill the Tyranid Norn-Queen commanding the Hive Fleet that was assaulting that world. Ventris and his trusted companion Lysane then joined the Inquisitor and the Deathwatch Kill-team in the assault on the Norn-Queen, but in this way were considered by the Codex Astartes to have "deserted" their posts as leaders of the Ultramarines 4th Company during battle. Despite their victory, accusations of severe dereliction of duty were levelled against both Astartes by their fellows, and Chapter Master Marneus Calgar imposed on both a Death Oath to find and destroy the Daemonculaba his Chief Librarian Varro Tigurius had received disturbing visions about through the Empyrean.
- The Horus Heresy - Book Six: Retribution (Forge World Series) by Alan Bligh, pg. 265
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- Brotherhood of the Moon (Novella) by Chris Wraight
- Grey Talon (Audio) by Chris Wraight
- Ultramarines Omnibus Volumes 1 & 2 (Novels) by Graham McNeil
- Bloodquest (Graphic Novel) by Gordon Rennie