The Warrior's Pilgrimage is an ancient tradition of the Adeptus Astartes. When a Space Marine feels that his honour has been irreparably compromised by a personal failure, he can request from his Chapter Master to be released on a Warrior's Pilgrimage. If granted permission, he will leave his Chapter and Battle-Brothers behind and head for the nearest Imperial warzone, throwing himself into the thickest of the combat against one of the Imperium's many enemies, and will keep doing so until he finally dies. Amongst the superhuman defenders of the Imperium of Man, this amounts to honourable suicide, for the Astartes will go into battle seeking death instead of victory, but will not accept death willingly.
The tradition of the Warrior's Pilgrimage has been inherited from the ancient time of the Great Crusade, where both individual Space Marines and entire Space Marine Legions would make 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 truly impossible thing 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.
Today, a Warrior's Pilgrimage is seldom requested. Space Marines are psycho-indoctrinated from the moment they are accepted as Aspirants to their Chapter to deal emotionally with the bloodshed they will commit and the inevitable casualities that accompanies a life of constant warfare. Also, whenever an Astartes feels an emotional burden, he will confess it to his company's Chaplain. These ancient warriors are masterful orators and keen students of the human psyche, and almost always find the right words to unburden their brethren and re-kindle the flame of their righteousness.
But it is not always so; terrible losses in battle, or the loss of a sacred artefact of their Chapter can unhinge the mental stability of a Space Marine beyond the ability of a Chaplain to set it right again. Such Astartes will often request to go on the Warrior's Pilgrimage, as a self-imposed punishment and a way to rid themselves of their guilt.
If his petition is accepted, the Space Marine will report to the Apothecarion to have his gene-seed extracted, and will then don his Power Armour, take his faithful Bolter and leave for the nearest warzone, seeking his redemption in death by facing the most powerful opponent he can find. For most of these Pilgrims, their first battle will also be their last; and their bodies and wargear will be solemnly returned to their Chapter if possible. Some Pilgrims will manage to survive despite the odds; these Astartes are choice recruits for Inquisitors seeking to add a fearsome superhuman warrior to their retinue. Sadly, some of these rare survivors lose their sanity completely and ultimately turn Renegade. It is for this last reason that many Chapter Masters are loath to give their permission for a Warrior's Pilgrimage: the loss of a capable Battle-Brother and his wargear is grave but honourable, while the stain on the Chapter's honour of a Battle-Brother on a Pilgrimage who turns Renegade is unbearable.
- Captain Taelos of the Imperial Fists - Taleos of the Imperial Fists was faced with the almost total annihilation of his 2nd Company against the Tau. He requested to go on a Warrior's Pilgrimage, but was turned down the first time, and put in charge of the 10th Company instead. After replenishing the ranks of the Imperial Fists, he made another request, which was granted by his Chapter Master.
- Captain Reinez of the Crimson Fists - Reinez of the Crimson Fists lost his 3rd Company's Company Standard to the Soul Drinkers on Ettymion IV. He resigned his rank and petitioned Chaper Master Pedro Kantor to find redemption in death. He resurfaced for the trial of the Soul Drinkers on the Phalanx where he was appointed as the prosecutor of those Renegade Space Marines by the Imperial Fists. Too consumed by his hatred, Reinez ultimately joined the Forces of Chaos in an assault on the Phalanx and died trying futilely to get his revenge on his hated foes.
- Lone Wolves of the Space Wolves - The Lone Wolves are the Space Wolves' version of those Astartes who undertake a Warrior's Pilgrimage. Lone Wolves are created when a Space Wolf Astartes becomes the sole survivor of his Pack. The Lone Wolf will swear an oath to face the most terrible of foes in personal combat, to bring his fallen Pack's saga to a close, and either join them in death, or start another saga as a member of the Wolf Guard when his oath is fulfilled. Unlike other Chapters, Lone Wolves still fight as a part of their company, albeit a distant and solitary warrior.
- Codex: Space Wolves (4th Edition)
- Sons of Dorn (Novel) by Chris Robertson
- Phalanx (Novel) by Ben Counter