Rusty " Rusty " was the name given by the Twelfth Doctor to a Dalek captured by the forces of Combined Galactic Resistance , due to the outer Dalek shell being old and damaged . Intrigued and worried by Rusty ' s desire to exterminate the Daleks , the Doctor decided to explore the possibility for a " moral Dalek " . Biography . Rusty lived a normal Dalek life , until one battle left him drifting alone in the depths of space ; unknown to him , his power source had cracked and was leaking radiation that disrupted his shell ' s programming to keep him from feeling anything but xenophobic hatred towards non - Daleks . Seeing the birth of a star triggered a realisation in Rusty of the inevitability of life returning despite the efforts of the Dalek s . From this , Rusty saw Daleks were evil and needed to be wiped from existence . Eventually , he was found by the Combined Galactic Resistance , and brought aboard their ship the " Aristotle " . They attempted to open the shell , hurting Rusty . Badly hurt already , Rusty asked for help in recovering so he could exterminate his own race . Interested in the idea of a moral Dalek , the crew promised him medical attention . The Doctor , Clara Oswald , Journey Blue , Ross and Gretchen Carlisle were shrunk and ventured into Rusty to try to fix the damage that was killing him . Using his sonic screwdriver , the Doctor repaired a crack in Rusty ' s power source that was leaking radiation and killing him . However , without the radiation affecting him , Rusty reverted to his original Dalek programming , restored to full power and went on a rampage , killing several soldiers and sending a distress call that attracted a nearby Dalek flying saucer . Upon urging from Clara , the Doctor decided to attempt to restore the changes once more . He had Clara reactivate the Dalek ' s suppressed memories so he could see the birth of the star again and be reminded of the universe ' s beauty . Clara succeeded and the Doctor telepathically linked with Rusty to show him more from inside his own mind . At first it seemed the Doctor had succeeded , as Rusty again saw beauty and divinity . However , Rusty also saw the Doctor ' s hatred of the Daleks , which resonated even more strongly with him . Rusty saw the Daleks as an evil which must be , in true Dalek fashion , exterminated . Rusty then went on a rampage against his own kind , slaughtering the Daleks attacking the " Aristotle " and fooling the saucer into retreating by falsely telling the other Daleks that the " Aristotle " s self - destruct had been activated . Rusty left with the Daleks to continue his efforts against them , telling the Doctor that although Rusty himself was not a " good Dalek " , the Doctor was a good Dalek . ( TV : " Into the Dalek " ) Rusty continued to fight the Daleks for billions of years . He isolated himself at the centre of the universe , in the ruins of Villengard , combating numerous Daleks that came to fight him . Rusty fended them off , positioning himself in a tower overlooking the battered city . The Twelfth Doctor , nearing his death , came to the lone Dalek with his original incarnation to gain information on the Testimony , as Rusty still had access to the Daleks ' Pathweb . Rusty attacked him . However , he eventually removed his Gunstick as a peace offering to the Doctor , who persuaded him to help as it would irritate the Daleks greatly . After providing him the information he desired , the Twelfth Doctor left Rusty . ( TV : " Twice Upon a Time " ) Memories . As a Dalek , Rusty was linked to Pathweb , the shared intelligence of the Daleks . ( TV : " Asylum of the Daleks " ) Through it , Rusty had access to the memories of Henry Van Statten ' s " Metaltron " exterminating Bywater as it escaped the Vault in the Battle of GeoComTex ( TV : " Dalek " ) and Davros ' New Dalek Empire attacking the " Valiant " during the 21st century Dalek invasion of Earth . ( TV : " The Stolen Earth " ) The destruction of the Daleks , the fleet and the Crucible at the failure of said invasion ( TV : " Journey ' s End " ) were memories Rusty saw while telepathically connected to the Doctor . ( TV : " Into the Dalek " ) Legacy . After the Twelfth Doctor ' s mind was connected to a mind scythe , the " holiday snaps " the Doctor showed Kygon Brox included Rusty . ( COMIC : " The Instruments of War " ) The Doctor remembered what Rusty had said to him when Missy offered him an army of Cybermen for his birthday that he could use to rule the universe . ( TV : " Death in Heaven " )