Octavian (The Time of Angels)

Octavian was a Bishop Second Class who had deployed Dr River Song on a covert mission which led to her presence on the Byzantium, that housed one Weeping Angel. When he arrived with his clerics at the crash site of the Byzantium, he was displeased with River until she introduced the Doctor, the "equivalent of an army" she had apparently promised for assistance.

While discussing their plan of action, Octavian questioned Song whether she had informed the Doctor of her true identity.

He led his men into the Maze of the Dead below the Byzantium, three of whom were soon killed by the Angel. 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 blue box. 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 pretends that he and River are engaged to accompany her and the Doctor to the flight deck. On the way he reveals that she's in his protective custody. At the flight deck, when River has already gone through, he is attacked by an angel, but it is frozen, trapping him, before it can kill him. He reveals to the Doctor that she killed a man "who many considered a hero" (but whose identity he feels the Doctor emphatically "[doesn't] want to know") and not to trust her. The Doctor refuses to leave him, but Octavian tells him to go, glad that his courage did not desert him in the end. When the Doctor states he wishes he knew him better, Octavian replies the Doctor knew him at his best, and he is presumably killed by the Angel as the Doctor leaves. (DW: Flesh and Stone)