Garran Crow is a Castellan of the Grey Knights Space Marine Chapter and a notable hero of that elite unit of Astartes. Crow is both the leader and Brotherhood Champion of the Grey Knights' order of Purifiers. Crowe is charged with the wardenship of the powerful artefact known as the Blade of Antwyr, a daemonic sword that continuously brings him into both physical and spiritual peril by tempting him with Chaotic promises of power or seeking to bind his will with black sorcery.
As both the leader and Brotherhood Champion of the Purifier order, Castellan Garran Crowe is considered a flawless soul, immune to the temptations of Chaos. Garran carries a burden greater than any of his Battle-Brothers, for he is charged with the wardenship of the Black Blade of Antwyr. This infamous artefact was first encountered during the latter years of the 37th Millennium, during the mad days of the Occlusiad, unearthed amongst the ancient ruins of a temple by the apostles of the Blind King. This daemonic weapon of prodigious power swiftly corrupted its discoverer's mind and body. Together, sword and slave made bloody war upon the Vidar, Tremayne and Darkspire Sectors, a war only ended by the intercession of all 8 Brotherhoods of the Grey Knights. The blade and its wielder both vanished into the Warp in the aftermath. Three thousand Terran years later, the foul blade reappeared in the material universe upon the doomed moon of Tethyrs, crossing paths with the Grey Knights once more. On this occasion, the blade's bearer was finally slain, and the custodianship of the foul artefact fell to the capable hands of the Grey Knights.
The Grey Knights proved unable to destroy the Blade of Antwyr as the Warp-spawned weapon was impervious to all means at the the Chapter's disposal. The Astartes of the Chapter proved reluctant to simply cast the dangerous artefact into the void of interstellar space where the Grey Knights knew that eventually a new bearer would be drawn to its evil aura. To seal it away in a vault within their Fortress-Monastery would be to invite the corruption of the chamber's guardians. A fateful decision was made to place the Black Blade of Antwyr into the safest prison the Grey Knights could conceive; the hands of the Chapter's own Purifiers. The Purifiers in turn placed the blade into the incorruptible hands of their Brotherhood Champion. For 1,000 standard years, the blade has been passed down from one incorruptible warrior to another, until finally reaching the hands of Garran Crowe.
The wardenship of the Blade of Antwyr constantly brings Castellan Crowe both physical and spiritual peril. When not beset by insane mortals and desperate daemons drawn to the sword's Chaotic siren song, Crowe must constantly do psychic battle with the blade itself, stemming its constant whispered temptations with his iron will. For the blade strives to tempt its guardian with promises of Chaotic power or bind his will with the black sorcery. The Castellan must forever remain on guard, for the sword constantly offers to lend its strength to his own in the pursuit of victory. Though many bearers would embrace such an offer, counting on their strength of will to control the sword without becoming corrupted themselves, Crowe has never succumbed to these temptations no matter how dark the hour or desperate the battle. Garran Crowe has remained incorruptible and inviolable, and intends to remain so until the day of his eventual death and union with the Emperor.
- Codex: Grey Knights (5th Edition), p. 42