Commander (The Pandorica Opens)
From Tardis Wiki, the free Doctor Who reference
The Commander was an Auton posing as a Roman commander. There were no real Romans featured in the episode, despite being the right period. He decided to help the Doctor and later placed him in the Pandorica. When the Doctor negated the Cracks in time, the Alliance was never created and the Commander never existed. (DW: The Pandorica Opens)