Thin One

The Thin One, along with his husband, the Fat One, were part of the Anglican Regiment of the Church stationed at Demons Run. The two seemed to have no names, instead using "the Thin One" and "the Fat One" to refer to each other. They both were discussing the Doctor's actions involving chasing the Atraxi from Earth after they captured Prisoner Zero and the fact that he called them back to scold them for almost roasting Earth. When Lorna Bucket asked them if they had names, they said that they were the "Thin/Fat Gay-Married Anglican Marines" and asked why would they need names.

His husband was taken to be initiated into the order of the Headless Monks, and when Colonel Manton later revealed what this entailed, he was understandably upset. When the Doctor hid himself in the Monks' robes, he opened fire on one of them in a panic, thinking it was the Doctor. (DW: A Good Man Goes to War)