Captain-General is the senior rank granted to the Chief Custodian, the senior-most member of the Emperor of Mankind's elite personal guard known as the Adeptus Custodes. The Captain-General personally oversees the select inner corps of three hundred Custodians, known as the Companions, who actually serve the Emperor as his personal bodyguards within the sacred chambers of the Sanctum Sanctorum, the Throneroom where the ancient prosthetic device known as the Golden Throne contains the ancient, withered corpse of the God-Emperor Himself. As the highest authority within the Adeptus Custodes, it is up to the Captain-General's discretion who may be allowed to be granted access to the Emperor. He also oversees the security of the Imperial Palace. Performing such sacred and important roles, the Captain-General is considered a very influential figure and serves as an important member of the Senatorum Imperialis.
- Constantin Valdor - Constantin Valdor was the Chief Custodian and Captain-General of the ancient Legio Custodes during the Great Crusade and the Horus Heresy. Just prior to the outbreak of the Horus Heresy, Valdor was charged by the Emperor to accompany the Primarch Leman Russ of the Space Wolves in bringing the Primarch Magnus the Red of the Thousand Sons to account for breaking promises he had made during the Council of Nikaea which had strictly forbidden the use of sorcery and psychic powers within the Imperium. Valdor, with a contingent of the elite Custodian Guard, fought alongside Russ and the Space Wolves during the Fall of Prospero. He and his forces were responsible for killing at least three of the greatest psykers of the Thousand Sons Legion and routing a force much more numerous than their own. He was also responsible for saving Bjorn the Fell-Handed when his arm was corrupted by the sorcerous powers of a Thousand Sons psyker. Valdor sliced Bjorn's arm off to prevent the corruption from overrunning his body. After Horus' betrayal became known to the Imperium, Valdor was present during the meetings of the Officio Assassinorum's Clade Sires and Siresses. It was Valdor who suggested that an Assassin from each Clade operate as a team to assassinate Horus, rather than act alone as was the standard mode of operation. It is currently known that after the Horus Heresy Valdor would become a High Lord of Terra, but would eventually step down voluntarily to protect his beloved Emperor.
- Beyreuth - Beyreuth was the Chief Custodian and Captain-General of the Adeptus Custodes during the mid-32nd Millennium, a relative peaceful and prosperous time within the Imperium's tumultuous oft-turbulent history. But in 544.M32, this temporary peace was shattered by the massive Ork WAAAGH! led by the Warlord known only as The Beast. Not since the Ullanor Crusade had the galaxy seen such a massive WAAAGH!, which eclipsed even the size of the ancient Ork Empire of Ork Overlord Urrlak Urruk. The Captain-General was present when the inner sanctum of the Imperial Palace was invaded by the Harlequin Troupe of the Joyful Tears. Beyreuth successfully led the defence of the Throneroom against the would-be interlopers, though at the cost of more than a dozen Adeptus Custodes. Only the Shadowseer Lhaerial Rey and the Death Jester Bho managed to reach the outer chamber which led to the Golden Throne, intent on meeting with the Emperor. The Death Jester was killed and the Shadowseer was pined to the ground. Lhaerial insisted that the Eldar had "come in peace," to deliver a message from Farseer Eldrad Ulthran, but the Captain-General refused to acknowledge her pleas. As he was about to order the death of the upstart xenos, the Captain-General was only halted by the timely intervention of Inquisitor Lord Veritus. The Beast and his WAAAGH! proceeded to rampage across the Imperium and into the very heart of humanity, threatened the Throneworld of Terra itself. The forces of the Imperium were only able to half this advance at great cost and desperate measure, but in the process, severely depleted the forces of the elite Adeptus Astartes.
- Codex Imperialis (2nd Edition) by Rick Priestley, pg. 12
- Warhammer 40,000: Rulebook (6th Edition) (Digital Edition), pg. 403
- Tales of Heresy (Anthology), "Blood Games," by Dan Abnett
- War of the Beast, Book 5: Throneworld by Guy Haley