Mire The Mire were a warrior race , purported to be one of the deadliest in the galaxy . Biology . Whilst wearing their armour , the Mire resembled large , clunky , metal robots . Underneath their helmets , they had small , lamprey - like heads with three circular rows of teeth . They fed on adrenaline and testosterone ; to acquire these substances , they would capture and liquefy individuals from other warrior races , and drink the resulting " nectar " . Culture . Although they were known across the galaxy as fierce and powerful warriors , the Mire were , in reality , an unskilled and inept army . They constructed their reputation by picking their battles carefully , only getting involved in fights with weak opponents to ensure they would always win . They also used their advanced technology to appear more powerful than they truly were , to intimidate their foes into submission . ( TV : " The Girl Who Died " ) Technology . The Mire possessed technology significantly more advanced than that of Earth . Their armour - which they wore even when out of combat - was equipped with wrist - mounted energy weapon s , whilst their helmets contained communicators and battlefield medical kits . The helmets could also generate hologram s , and transmit those holograms to other Mire soldiers . Though the Mire considered this technology an advantage , their reliance on " viewing reality through technology " was a weakness according to the Doctor . The Mire ' s spacecraft was enormous and capable of travelling at great speeds through both air and the vacuum of space . It contained the facilities used by the Mire to liquefy their captives and extract the desired chemicals ; it also contained their weapon forges . Though the scale and exact purpose of the forges was uncertain , they were loud enough to create sounds similar to thunder when operated from within a planet ' s atmosphere . The Mire would operate their forges before going into battle , to incite fear in their opponents . Though their technology was highly developed , the Mire were unsettled by the sonic sunglasses , which - as noted by Clara Oswald - were " technology from a civilisation vastly more powerful than [ their ] own . " ( TV : " The Girl Who Died " ) History . The Twelfth Doctor and Clara Oswald encountered the Mire in a 9th century Viking village on Earth , after their leader - disguised as the Norse god Odin , whom the Vikings worshipped - projected a holographic image of himself across the sky . He invited the warriors of the village to dine with him in Valhalla , but this was a trap ; in actuality , the Mire transported the warriors to their ship , where they were liquefied for sustenance . Clara and Ashildr were also teleported aboard the ship , but were spared because they possessed the sonic sunglasses ; the Mire feared the advanced alien technology the glasses represented . Though Clara was almost successful in persuading the Mire to leave Earth in peace , Ashildr - distraught after the death of her friends - declared war on the Mire , vowing to " crush [ them ] on the fields of battle . " Their leader , eager to defeat the already crippled village , accepted the challenge and beamed Clara and Ashildr back down to Earth . When " Odin " arrived in the village with ten Mire footsoldiers the following morning , they found the villagers not preparing for combat , but partying and dancing . Confused , they failed to realise that the celebration was a distraction ; the villagers , under the command of the Doctor , had constructed an elaborate trap for the Mire , which involved using electric eel s and metal wiring to play havoc with their equipment . The plan culminated in Ashildr using a stolen Mire helmet to project the image of a terrifying sea dragon over a harmless wooden puppet , which the Mire were convinced was real . Outmatched , they fled to their ship , leaving their leader alone . Afterwards , the Doctor revealed the truth of the deception and also revealed that Clara had recorded the entire humiliating defeat on her mobile phone . On danger of having the footage uploaded to the Galactic Hub , " Odin " and the rest of the Mire fled the planet , promising to one day enact vengeance . ( TV : " The Girl Who Died " ) A Mire battle helmet ended up in UNIT ' s Black Archive in the early 21st century . ( TV : " The Zygon Inversion " ) Similarly , a helmet was also found inside the Matrix on Gallifrey , suggesting that the Mire once tried to infiltrate the Matrix but were captured by the Cloister Wraith s . ( TV : " Hell Bent " ) Behind the scenes . According to DWA15 12 the Mire planned on launching a surprise invasion of Earth in 2016 . UNIT cracked the code of their invasion plans and deciphered it , with the help of the reader . The Mire ' s secret message was , " Let us feast on their warriors " .