Octavian (The Time of Angels)
Father Octavian was a Bishop Second Class who had deployed Doctor River Song on a covert mission. This led to her presence on the Byzantium, which housed a Weeping Angel. He had great respect for the Doctor, knowing of his great feats. Octavian toke his job seriously, putting up with River as much as he could. In his last moments, he made sure that the Doctor did not learn more than he had to about why River is in prison.
Biography
Learning of a dormant Weeping Angel in possession of an unknowning fool, Octavian had River Song released into his custody to help in return for earning her pardon for the "murder" of the Doctor. With River promising the "equivalent of an army" later, Octavian had her infiltrate a party being held on the Byzantium to confirm the Angel's existence and try neutralizing it.
Being later called down to the crash site of the Byzantium, he was displeased with River, until she introduced the Eleventh Doctor, the "equivalent of an army" she had promised earlier. Learning that they would need to infiltrate the Maze of the Dead below the Byzantium in order to reach the Angel, Octavian had the clerics set up explosives while he was informed by the Doctor and River about the nature of the Weeping Angels.
While discussing their plan of action, Octavian asked Song whether she had informed the Doctor of her true identity. Something he found bad news for the Doctor to learn of when she told him "no"; to make sure the Doctor helped, Octavian made sure she kept her mouth shut about it.
He led his men into the maze with the Doctor, Amy and River. Three were soon killed by the Angel from the crash. The Doctor assured him they could not have been saved, but Octavian reminded him that he would be the one to tell their families while the Doctor went off in his little blue box. Later, much to his horror, he learned that all the statues in the maze were actualy deformed/starving Angels. Nonetheless he still told the Doctor he had faith in him when they were surrounded by Angels. (DW: The Time of Angels)
After entering the forest vault, he claimed River and he were engaged so he could accompany the Doctor and her to the flight deck. On the way he revealed she was in his custody. At the flight deck, when River had already gone through, he was attacked by an Angel. With the Doctor looking at it, it was frozen, trapping Octavian in a headlock, before it could kill him. He told the Doctor that River had killed a man who was "a hero to many", but felt that he "really don't want to know" who it was. He warned the Doctor not to trust her. The Doctor refused to leave him, but Octavian told him to go, glad that his courage had not deserted him in the end. When the Doctor said he wished he knew him better, Octavian replied that the Doctor knew him at his best. He was presumably killed by the Angel as the Doctor left. (DW: Flesh and Stone)
