Nimon The Nimon were a parasitic species that operated on a galactic scale , using up civilisations and moving on . Biology . The Nimon were large , black - skinned humanoid s with bull - like heads , similar to the minotaur s of Earth ' s myths . Their horns could shoot out blasts of energy . Nimon drained energy directly from their victims , leaving them as husks . They had mighty , rumbling , echoing voices . ( TV : " The Horns of Nimon " ) They were related to another minotaur - like species . ( TV : " The God Complex " ) Culture . The Nimons would feed on the population of an entire world , usually consuming it to extinction within a few years . As their food source got scarce , they would look for another planet ripe for conquest and draining . Usually , one Nimon was sent to a planet , representing itself as a god with advanced technology . It would construct a maze - like Power Complex , a building - sized labyrinth of circuitry designed to generate a pocket black hole back to the Nimons ' current planet . The Nimons would then migrate en masse to the new planet using capsules transmat ted through the black hole . The Nimons would then drain that world dry and look for the next , continuing the cycle . They referred to this as the Great Journey of Life . ( TV : " The Horns of Nimon " ) The Nimons were very keen to conduct the Great Journey of Life to Earth , due to its prime position in the galaxy . From there , various alignments could offer millions of worlds for the Nimon migration to attack . ( AUDIO : " Seasons of Fear " ) Technology . Nimons were able to transport capsules , a similar idea to transmat capsule s , between worlds without the use of black hole s , but the prospect used a considerably larger amount of energy , and was only possible when those planets were in a particularly beneficial galactic alignment . The process was made much easier if they could construct any sort of " ground station " on the invading world . Once a Power Complex was built to generate a black hole , alignment of the planets was no longer necessary . ( TV : " The Horns of Nimon " ) Among the tools the Nimons had were psionic mind beam s and gravitational lensing . With a black hole established , they could phase energy and matter through its event horizon . ( AUDIO : " Seasons of Fear " ) They also used gravity device s . ( PROSE : " GodEngine " ) Besides being able to draw energy from the binding forces of organic matter , they could also transmit energy in the opposite direction . The process was capable of providing a person near - immortality , and is theorised could make a person fully immortal and invulnerable if given a full charge . ( AUDIO : " Seasons of Fear " ) History . The Nimon homeworld was a planet inhabited by Nimons . Exile from it was considered a cause for shame . ( COMIC : " Space in Dimension Relative and Time " ) The Nimons were one of the many races that participated in the Millennium War against the Mad Mind of Bophemeral . They collaborated with the Osiran s in dropping quantum collapser s on the Mad Mind . ( PROSE : " The Quantum Archangel " ) In Earth ' s ancient times , Earth had seen the appearance of a Nimon scout . Before the scout could set himself up as a god , he was attacked by a group of heroes , led by the warrior Mithras . The heroes managed to take the Nimon ' s own sword ( specially tempered by travel through a black hole ) and kill the beast with it . The tale of Mithras slaying the bull became legend with the advent of a new religion . By 305 AD , the sword and a communicator were holy relics of the Mithraic religion , being used in ceremonies in Roman Britannia . The Nimons contacted the legionnaire Sebastian Grayle and offered him immortality if he would set up the ground station and sacrifice needed to establish a link between the Ordinand System and Earth . The Eighth Doctor arrived shortly before the sacrifice and thwarted the plan , but not before giving Grayle near - immortality . Over the next 1500 years the stars aligned properly for two more attempts , but the Doctor was on hand at each time to prevent Grayle and the Nimon from succeeding . Although they almost succeeded in conquering Earth , the Doctor was able to avert the invasion by taking the future Grayle back in time to confront his past self at a point when the energies that gave him his immortality had been depleted . Disgusted at the sight of what he would become in the future , the past Grayle killed his future self , vowing to never become him and averting the chain of events that led to him becoming the Nimons ' servant . ( AUDIO : " Seasons of Fear " ) Sometime in the future , the Nimon had finished with their latest planet Crinoth , and were looking to migrate to Skonnos , home of the faded Skonnan Empire . The Nimon scout set himself up as the local god , promising the Skonnan leader Soldeed the power he would need to make Skonnos a great empire again . Soldeed demanded a tribute of hymetusite crystals from neighbouring planet Aneth for the power source . The Fourth Doctor and his companion Romana II happened upon the planet , and stopped the migration with the help of human sacrifices also sent from Aneth , leaving the Nimon trapped on Crinoth as it exploded . ( TV : " The Horns of Nimon " ) The Nimon invaded a planet , and took its princess , Jahanna , captive . They sent a wormhole device to another world in preparation for the next invasion . Unbeknownst to them , a native of the other world , Jak had snuck through the wormhole . Jak saved the princess by knocking one of the Nimon unconscious . He then escaped with Jahanna back to his world and destroyed the Nimon ' s wormhole device . ( PROSE : " Jak and the Wormhole " ) Alternate timeline . In an alternate timeline , the Nimons succeeded in their invasion of Earth , and used that prime location to eventually replace the Time Lord s and become total masters over space and time . In this timeline they even possessed to power to create other alternate timelines , illusions to mask the reality that they controled . The Eighth Doctor ' s interference with Sebastian Grayle prevented this timeline from occurring . ( AUDIO : " Seasons of Fear " ) In another alternate timeline , a lone exiled Nimon drained the planet Datastore 8 of all its resources , knowledge and energy to create a black hole with the intention of destroying the Nimon homeworld . It then called the Doctor ' s TARDIS to use its engines to activate the bomb . The Eleventh Doctor undid this by going back in time and preventing the Nimon from subjugating Datastore 8 . ( COMIC : " Space in Dimension Relative and Time " ) References . During the Eleventh Doctor ' s stay on Trenzalore , he would tell stories of his encounters with the Nimon to the townspeople of Christmas . ( PROSE : " An Apple a Day . . . " )