Battle of Zaruthstra

The Battle of Zaruthstra was a conflict that took place in the year 4037. It is known that one side were human. The disgraced Sontaran Commander Strax acted as a Nurse for this side, tending to soldiers from the battlefield. The Doctor's TARDIS landed on the battlefield: a summon to Strax, who owed him a debt, to help in his mission to rescue Amy Pond and her baby at Demon's Run. (DW: A Good Man Goes to War)

Captain Harcourt referred to the enemy as "those things", suggesting they were extremely different to humans.