K9


 * For the TV series see K9 (TV series)

K9 is the designation given to a series of intelligent dog-like robots who have served as companions for the Doctor, Leela, Romana and Sarah Jane Smith. The robots' name is often presented as K9 with no hyphen (The Adventures of K9).

K9 Mark I
Professor Marius, who invented the first K9, describes him as "My best friend and constant companion." Marius used to have a dog on Earth but because weight requirements did not allow him to bring his real dog from Earth into space so he created K9. (DW: The Invisible Enemy) However, K9 may owe his existence to a temporal paradox. According to one account, the Professor copied the remnants of one of the version of K9 created by the Doctor and given to Sarah Jane Smith. (DWM: Tautology)

The Professor offered K9 to the Doctor as the same weight requirements made him unable to take Mark I back to Earth with him. (DW: The Invisible Enemy) After a number of adventures with Leela and the Doctor, Mark I decided to stay on Gallifrey with his "mistress". (DW: The Invasion of Time).

''The Fourth Doctor and K9 Mark II spent an indeterminate period of time together. However, in the next episode, DW: The Ribos Operation, the Doctor appeared to be activating K9 Mark II, giving the implication only that no significant time had elapsed since leaving Gallifrey.''

There are (possibly apocryphal) accounts that this model of K9 later performed missions on behalf of the Time Lords and was given control of a space vessel called K-NEL (The Adventures of K9: K9 and the Time Trap, et al).

K9 accompanied Leela on Gallifrey for many years, but it was only after the disappearance of her Time Lord husband, Andred, that Leela and her K9 met Romana and her K9 (the two K9 units did not get on well and competed with each other). (BFG: Weapon of Choice) After Leela became Romana's bodyguard, and after many important missions on her behalf, Leela's K9 was destroyed in a bomb explosion, leaving Leela heartbroken, but refusing to allow a duplicate unit to be built in its place. (BFG: Imperiatrix)

At one stage, he chased two Jixen to 2050 Earth and self-destructed. (K9TV: Regeneration)

K9 Mark II


At some point prior to this, the Doctor obtained or constructed at least one (possibly more) backup models of K9, and immediately after leaving Mark I behind with Leela, the Doctor unpacked K9 Mark II. This version of K9 accompanied the Doctor and new companion on their quest to locate the segments of the Key to Time (DW: The Ribos Operation), however the swampy terrain of Delta III made it impossible for him to accompany them there. At the conclusion of the quest, the Shadow turned K9 to his evil will, during which time K9 assumed a sinister personality. (DW: The Armageddon Factor)

The Doctor found that K9 had contracted laryngitis and had lost his voice as a result of this. K9 was left in the TARDIS while the Doctor and Romana battled the Daleks and Davros (DW: Destiny of the Daleks). During a subsequent adventure, it remained patiently in the TARDIS, which would imply that his voice had not yet returned. (DW: City of Death) After the return of his voice, it sounded quite different and remained so for a number of adventures (DW: The Creature from the Pit). However, later the familiar voice returned. (DW: The Leisure Hive)

Damaged by the time winds, K9 Mark II could not cross back into N-Space with the Doctor, so decided to stay behind at the Gateway with Romana, to help her free the remaining Tharils from slavery. (DW: Warriors' Gate) Eventually, however, Romana and the presumably repaired K9 returned to their own universe, and K9 Mark II came to live on Gallifrey. (NA: Lungbarrow, WC: Shada)

During Romana's Presidency of Gallifrey, Leela became her bodyguard, and the two K9 units were forced to work together, not always amicably. After Matthias had replaced Romana as President, he nominated her to undertake a mission to find a cure for the Free Time virus, to be followed by exile. K9 opted to remain in the employ of Matthias, fighting the infection on Gallifrey. However, Braxiatel and K9 had planned another operation. Realising that the only cure to the virus was to end the regeneration capabilities of the Time Lords, Braxiatel used a Time Scoop to collect the Time Lord bio-data archive (along with with K9). Romana was then asked to decide whether to administer the cure, or to let Gallifrey die and rebuild it from scratch with the bio-data archive. Her decision is not known. (BFG: Gallifrey)

The fates of K9 in light of the Last Great Time War remain unknown.

K9 Mark III
A third model, K9 Mark III (again either obtained or constructed by the Doctor) was shipped to Sarah Jane Smith in 1978 to serve as her companion, but she did not receive his gift until 1981. Afterwards, K9 assisted Sarah Jane in defeating the Hecate Cult of Moreton Harwood. (KAC: A Girl's Best Friend) Circa 1983, K9 Mark III still lived with Sarah Jane, but, by chance, did not accompany her to Gallifrey. (DW: The Five Doctors) K9 accompanied Sarah to an archaeological dig in Egypt. (DWM: City of Devils) In the early 1990s, K9 assisted Sarah in investigating a supposedly haunted house. (VD: Housewarming)

In 1996, Sarah used K9 to hack into records and find Sam Jones' home address, and later to translate Lost Boy's speech. (EDA: Interference - Book One) K9 was briefly possessed by a malevolent entity, but was freed when Sarah accidentally electrocuted him. (ST: The Sow in Rut) K9 began slowly breaking down and eventually ended up deactivated in a cardboard box in Sarah's attic. (VD: Moving On) Hilda Winters had K9 dismantled and analysed. (BFSJS: Mirror, Signal, Manoeuvre)

Sarah, unable to find anyone to fix the robot, continued to carry K9 in the boot of her car, until a chance encounter with the Doctor in the mid-2000s resulted in K9 being restored to functionality. This served to be only temporary, however, as Mark III self-destructed in order to help the Doctor and his companions defeat a Krillitane invasion (DW: School Reunion).

K9 Mark IV


After Mark III sacrificed himself to defeat the Krillitanes, the Doctor left a new model, Mark IV, for Sarah Jane Smith, just seconds after he departed in his TARDIS (It's not known if the Doctor quickly built Mark IV from scratch or had it in storage). K9 refers to himself as being rebuilt and improved, suggesting Mark IV possesses the same memory as Mark III. (DW: School Reunion) Though Sarah Jane didn't find this out right away, the Doctor had also placed some gifts in a panel in K9's side: sonic lipstick and a Scanner Watch that could detect alien life.

A year before Sarah Jane first met Maria Jackson, K9 Mark IV left Sarah Jane in order to stabilise a dangerous artificial black hole in space which had been created in Switzerland. He could only speak with Sarah Jane occasionally via a cabinet with a spacetime link when the orbit of the black hole intersected with that of Earth and did not know when he would complete the job. (SJA: Invasion of the Bane) However, at times he was capable of returning to Earth very briefly during emergencies, and did so on two later occasions in order to render vital assistance. In the first time, he fought Mr Smith in pitched battle to allow Sarah Jane to upload the Armaggedon Virus, (SJA: The Lost Boy) and again in order to quickly upload TARDIS base codes to Mr Smith and assist the Doctor in returning the Earth to its correct location in space. (DW: Journey's End)

After these events he went back monitoring the black hole only to find an unidentified member of the Slitheen family attempting to steal him as part of a revenge plot against Sarah Jane who had foiled their plans in the past. K9 banished the Slitheen, after reversing one of its attacks.(SJA: From Raxacoricofallapatorius With Love)

K9 was eventually able to return when Ship used the black hole as fuel. Though Sarah Jane, Luke, Rani and Clyde were happy to have K9 back, Mr Smith was not. (SJA: The Mad Woman in the Attic) He then spent a lot of his time in Sarah Jane's attic at 13 Bannerman Road, but left in order to defeat Travist Polong. He was then present at Sarah Jane's wedding to Peter Dalton, where he helped the Doctor, Luke, Rani and Clyde to defeat The Trickster. (SJA: The Wedding of Sarah Jane Smith) He was then summoned to the International Gallery when Luke put Clyde's drawing of him inside a cloud of mystic drawing-animation energy and he defeated The Abomination, before returning to the attic. (SJA: Mona Lisa's Revenge) He then helped defeat the Slitheen family, before he was brought to Park Vale Comprehensive School by Clyde to help him with his test. He then helped defeat the Rakweed, before returning home. (SJA: The Gift)

In 2056, Sarah left K9 to a boy who would help later alongside with Drax to help search for the Sixth Doctor who was held captive by Omega. (Search for the Doctor)

2050 K9


After Mark I sacrificed himself to destroy Jixen warriors, a boy called Starkey retrieved his regeneration circuit and he was rebuilt as a much more advanced model, but had no memories of the Doctor. He stayed at the house of Alistair Gryffen, where he ran tests on K9, but did not tell The Department. K9 tried to kill Starkey, as he was sprayed with Jixen genetic matter and therefore registered as a Jixen. Starkey managed to convince him that he was not an enemy and K9 gave him his dog whistle so that he can be summoned whenever needed. (K9TV: Regeneration)

Personality
K9 had a very consistent personality from model to model. He had a polite, formal manner with just a hint of pedantry bordering on condescension. Though he often displayed feelings such as sorrow (DW: The Invasion of Time) and self-regard (DW: School Reunion), he often stated that he had not been programmed to have emotions. (SJA: Invasion of the Bane)

He did not use contractions just as "you've" for "you have" and addressed others by titles such as "Master", "Mistress", "Doctor-Master" (to refer to the Doctor) or "Young Master" (Adric and in one instance Clyde). Though he did not seem to resent his subordinate status, he tended to side with the Doctor's companions over the Doctor himself and at times showed a dark side, regarding other artificial intelligences with contempt (DW: The Invasion of Time) and relishing a brief chance to act as a figure of power. (MA: The Well-Mannered War) He usually did not engage in computer-like literal thinking, though on one occasion he followed Romana's instructions to "forget it" to the letter and erased all his knowledge of tennis from his memory banks. (DW: The Stones of Blood)

Because of him having great intelligence, he liked to bore people with facts and did not immediately stop when asked as he did to Leela on Pluto. When being told that he would have to stay behind in the TARDIS, K9 often argued, giving the Doctor reasons why he should go such as "[he] would be a good dog." This showed K9's willingness to assist the Doctor. He was also showed to have great intelligence and skill at chess as he was able to beat the Doctor in six moves (but this may only have been because he was programmed with all chess games since 1886). (DW: The Sun Makers, The Androids of Tara) K9 was revealed to have an aggression mode. (DW: State of Decay)

Features


The mechanics of K9 Mark I included rotating ear-probes, telescopic 'eye' probe, extendable nose concealing a powerful laser weapon, flashing lights on the top and the 'eye' panel, waggling tail antennae, and ticker-tape tongue. The head could also move up and down. The shell was painted in gold/grey metallic. Around K9's neck was a tartan collar, from which hung a silver disk. (DW: The Invisible Enemy)

After K9 Mark I was left behind with Leela on Gallifrey, The Doctor built a improved K9 Mark II. While the cosmetic changes were minimal (including the new metallic charcoal paint-work), in terms of series continuity K9's character underwent a vast change. Gone was the product of 5000 AD technology, as was the case with Marius's version. This new K9 was a product of the Doctor's own technology and values. The gun was now only capable of stunning, not killing and K9 now responded to a dog-whistle. K9 also featured a vast memory-bank, seemingly a mixture of the Mark One model, the Doctor's own memory and knowledge, and that of the TARDIS. (DW: The Invasion of Time)



When the Doctor left Sarah Jane Smith on Earth, he created K9 Mark III to be Sarah's new companion. The new mechanics of K9 Mark III included larger wheels in conjunction with a front and back-wheel drive. K9 was also given a brand new coat of paint (this time a metallic-blue) and a handle on the top of the shell to make carrying him easier. (KAC: A Girl's Best Friend)

When the Doctor created K9 Mark IV to replace K9 Mark III, he added a shiny metallic blue paint job and a number of improvements over Mark IV including an omniflexible hyperlink facility. (DW: School Reunion) Later, though, K9 reverted to his old, dark green color. (SJA: Invasion of the Bane) In battling Mr Smith (and following the battle) K9 displayed a teleport facility and utilizes a laser weapon similar to the previous K9s'. (SJA: The Lost Boy)

Marks

 * K9 Mark I: left behind with Leela on Gallifrey: Blown up by a bomb on Galifrey (Galifrey, Impedatrix)
 * K9 Mark II: left behind with Romana in E-space: Presumably, still with Romana
 * K9 Mark III: left behind with Sarah Jane Smith on Earth: Blown up saving Defry Vale from the Krilitanes in 2006
 * K9 Mark IV: a new body for Mk III when it was destroyed in a Krillitane invasion. (On Earth with Sarah Jane Smith)
 * K9 (2050): The regenerated form of K9 Mark 1.
 * Orthrus: A duplicate of K9 (2050) created by Drake to frame K9.

Behind the Scenes

 * In an interview, the writers originally wanted to name K9 "Pluto", after the Disney character; however, Disney refused permission.