Doctor Who: 5 Best Uses Of Classic Monsters In NuWho

Like his eventual boss, Madame Vastra, Strax first appears in A Good Man Goes To War. Having been sentenced to serve as a nurse on human battlefields as punishment for an attempted Sontaran invasion on Earth, Strax is overjoyed when The Eleventh Doctor summons him to take up arms in the Battle of Demon's Run.

At first believed killed in the battle, a later minisode revealed that Strax had simply fainted after receiving a minor wound. Unable to face the embarrassment of such a defeat, Strax accepts an invitation to join Vastra and Jenny back in Victorian London, where he serves as Vastra’s butler and carriage driver. Strax becomes the main comic relief of the trio, with his tendency to offer violent Sontaran solutions in situations that do not at all warrant such a reaction. Other humorous moments include his belief that River Song's hair is just a big head, and frequently mistaking Clara Oswald for a boy.

Strax became popular enough to appear in a pre-feature message for fans who saw Day of The Doctor in Theatres, and is easily the most loved Sontaran character in the history of the show.