"This is war and there can be no mercy." ― Father Carden[source]
Father Carden is described as an Evangelist and purist who vows to rid the world of magic.
The leader of the Red Paladins, he begins a bloody campaign against the Fey, determined to wipe their kind from the face of the Earth. He considers his campaign righteous, but it ultimately puts him at odds with King Uther Pendragon, whose popularity wanes as the campaign wreaks havoc throughout the countryside, instilling terror in the people. When Uther makes a deal with Nimue, the "Fey Queen," he switches his allegiance to Cumber the Ice King in a final bid to try to do in the Fey once and for all. His forces manage to root out Nimue and he declares that even though she is not in possession of the Sword of Power at the time, it is time to rid the kingdom of her once and for all. Raising a sword, he moves in to do the deed himself, but before he can, Morgana in the form of the Widow appears between them. She returns the Sword of Power to Nimue, who uses it to sever Father Carden's head, then everything erupts into chaos.
"Have you no pride? The witch mocks us. But mark my words: if I burn, I'll not burn alone." ― Father Carden, chastising the Weeping Monk for his failures at finding Nimue[source]
He is an evangelist and a purist who has vowed to rid the world of all magic. He is utterly sure of himself, convinced that he is doing the Lord's work. His campaigns show no mercy, burning entire villages and relentlessly slaughtering even young children. He employs many servants and is not above methods such as torture, even though he himself may not be the one doing the actual torturing. He considers himself above politics and therefore has trouble grasping why anyone might oppose him even if they seemingly agree that his cause is just. He is a pragmatist who is willing to work with anyone who will support his cause, even raising one of his sworn enemies as his own because of that enemy's ability to sense others of his kind.
According to Merlin, Father Carden was born on a "nothing town." Rather than actually see God in the Church, he saw an opportunity to crawl out of it when the clergy took him. Pope Abel, however, would not take him and since he couldn't buy his way in, he offered blood and ash instead.
He served at the pleasure of Pope Abel and seemed both fear and respect him. Although the Pope valued the services of him and his Red Paladins in hunting the Fey, he was losing patience with him due to his failure to capture Nimue.
The Weeping Monk
He found the Weeping Monk as a young child and formed him into a weapon against his own people. He twisted him by telling him that he was impure, but that through working with the Red Paladins, he could be cleansed. As the Monk's ability to sense fellow members of the Fey was the skill he valued most in him, he became irritated with the Monk for his failures in tracking down Nimue.
As the eventual leader of the people that Father Carden had sworn to wipe out, Nimue was Carden's mortal enemy. Despite this, he seemed to have a certain respect for her abilities, designating her "the Wolf-Blood Witch" following her slaughter of many wolves using the Sword of Power. He desired to capture her and torture the whereabouts of the sword out of her, but ultimately decided that he cared more about her death even if he did not get the sword because of the humiliating defeats he and his men suffered because of her. In the end, however, it was her who killed him by beheading him with the sword.