Editing Time Lord (section)

===Regeneration===
[[File:Regeneration 4-5.gif|thumb|right|The Fourth Doctor regenerates into the Fifth Doctor (from ''[[Logopolis]]'', 1981).]]

Time Lords also have the ability to regenerate their bodies when their current body is mortally wounded. This process results in their body undergoing a transformation, gaining a new physical form and a new personality.

Regenerations can be traumatic. In ''[[Castrovalva (Doctor Who)|Castrovalva]]'', the [[Fifth Doctor]] requires the use of a Zero Room, a chamber shielded from the outside universe that provides an area of calm for him to recuperate. The Time Lord's personality also sometimes goes through a period of instability following a regeneration, such as in ''[[The Christmas Invasion]]''.

It was first stated in ''[[The Deadly Assassin]]'' that a Time Lord can regenerate twelve times (thirteen incarnations in all).<ref name="The Deadly Assassin"/> There were exceptions to this rule, however: when the Master reached the end of his regenerative cycle, he took possession of the body of another person to continue living.<ref name="traken">{{cite serial |title=[[The Keeper of Traken]] |series=Doctor Who |series-link=Doctor Who |first=Johnny (writer) |last=Byrne |author-link=Johnny Byrne (writer) |first2=John (director) |last2=Black |author-link2=John Black (director) |station=[[BBC]] |location=[[BBC1]] |date=31 January – 21 February 1981 }}</ref> In "[[The Five Doctors]]", the Master was offered a new cycle of regenerations by the High Council to save the Doctor from the Death Zone, which may indicate that there are methods to circumvent the twelve regeneration limit. The Master says in "[[The Sound of Drums]]" <ref name="Sound of Drums"/> that the Time Lords "resurrected" him to fight in the [[Time War (Doctor Who)|Time War]]. It was revealed in ''[[The Brain of Morbius]]'' <ref name="The Brain of Morbius">{{cite serial |title=[[The Brain of Morbius]] |series=Doctor Who |series-link=Doctor Who |first=Robin (writer) |last=Bland |author-link=Robin Bland |first2=Christopher (director) |last2=Barry |author-link2=Christopher Barry |network=[[BBC]] |station=[[BBC1]] |date=3–24 January 1976 }}</ref> that the Time Lords also use the Elixir of Life in extreme cases, where regeneration is not possible. It is confirmed in "[[The Time of the Doctor]]" <ref name="totd"/> that a Time Lord can normally regenerate only twelve times but that the Time Lords have the ability to grant more regenerations: at the behest of [[Clara Oswald]] they granted the Doctor himself a new cycle when he was at the point of death from old age, having used up his entire cycle.

Regeneration, regardless of how many regenerations the individual Time Lord has already undergone, is a conditional and non-inevitable phenomenon. This is stated in "[[The End of Time (Doctor Who)|The End of Time]]" when the Tenth Doctor explains to [[Wilfred Mott]] that a Time Lord can die before they have a chance to regenerate, in which case they die outright.<ref name="end of time one"/> In ''The Deadly Assassin'' at least one of the murders was carried out with a 'staser', possibly a weapon designed to both kill and prevent regeneration (stasers are also stated to have little effect on non-living tissue).<ref name="The Deadly Assassin"/> In the Series 4 episode "[[Turn Left (Doctor Who)|Turn Left]]",<ref name="Turn Left">{{Cite episode |title=Turn Left |episode-link=Turn Left (Doctor Who) |series=Doctor Who |series-link=Doctor Who |first=Russell T (writer) |last=Davies |author-link=Russell T Davies |first2=Graeme (director) |last2=Harper |author-link2=Graeme Harper |network=[[BBC]] |station=[[BBC One]] |date=21 June 2008 |series-no=4 |number=11 }}</ref> the Tenth Doctor's body is shown on a stretcher following the parallel events of "[[The Runaway Bride (Doctor Who)|The Runaway Bride]]". A [[UNIT]] officer states that the Doctor's death must have been too quick to allow for regeneration.

In ''[[Destiny of the Daleks]]'',<ref name="destiny"/> Romana showed the ability to rapidly change form several times in a row during her first regeneration, and apparently had the ability to change into whatever appearance she desired. When the Doctor remarks upon her ability, she comments that he should have stayed in university. However, despite showing several appearances, Romana regenerated only once on that occasion.

In "[[Utopia (Doctor Who)|Utopia]]",<ref name="Utopia"/> the Master, just before regeneration, claimed that he would become "young and strong", implying that he could choose the form of his new body. The human-Time Lord hybrid River Song in "[[Let's Kill Hitler]]" claimed she was "focusing on a dress size", but subsequently weighed herself, seeming unsure of how her new body had truly developed.<ref name="hitler">{{Cite episode |title=Let's Kill Hitler |episode-link=Let's Kill Hitler |series=Doctor Who |series-link=Doctor Who |first=Steven (writer) |last=Moffat |author-link=Steven Moffat |first2=Richard (director) |last2=Senior |network=[[BBC]] |station=[[BBC One]] |date=27 August 2011 |series-no=6 |number=8 }}</ref> The Doctor said on several occasions he wished he was "ginger", which he has seemed unable to control in previous regenerations.<ref name="end of time two"/><ref name="Christmas Invasion"/> In "[[Last of the Time Lords]]",<ref name="Last of the Time Lords"/> when the Master is fatally wounded, he chooses not to regenerate, essentially committing suicide rather than regenerate and be kept prisoner by the Doctor forever. This again implies that regeneration is not inevitable and can indeed be refused.

Upon encountering the remains of fellow Time Lord the Corsair in "[[The Doctor's Wife (Doctor Who)|The Doctor's Wife]]", the Doctor refers to the Corsair as both male and female, hinting that Time Lords can switch genders upon their regenerations;<ref name="doctors wife"/> this is confirmed in "[[Dark Water (Doctor Who)|Dark Water]]", in which [[The Master (Doctor Who)|the Master]], previously seen in various male incarnations for over forty years, returned as a female. The  Doctor also regenerated as a woman in "[[Twice Upon a Time (Doctor Who)|Twice Upon A Time]]", as the [[Thirteenth Doctor]]. Though the possibility of Time Lords changing sex at regeneration was not explored directly in the classic series, ''[[The Hand of Fear]]'' depicts the Kastrian Eldrad going from female to male which he compared to Time Lord regeneration, implying the process could produce a change in sex.

Whether or not Time Lords can recognise each other across regenerations is not made entirely clear:
* In ''[[The War Games]]'',<ref name="The War Games"/> the [[The War Chief|War Chief]] recognises the [[Second Doctor]] from a previous (offscreen) encounter prior to his regeneration. However, his comments make it unclear whether he has merely deduced the Doctor's identity based on the circumstances of the TARDIS's theft and the Doctor's ability to pilot it.
* In ''[[The Three Doctors (Doctor Who)|The Three Doctors]]'',<ref name="The Three Doctors"/> the [[Second Doctor]] recognises the [[Third Doctor]] immediately, despite the fact that the Third Doctor is a future incarnation of himself. Omega is similarly able to recognise the two Doctors as the same man.
* In ''[[Terror of the Autons]]'',<ref name="terror of the autons">{{cite serial |title=[[Terror of the Autons]] |series=Doctor Who |series-link=Doctor Who |first=Robert (writer) |last=Holmes |author-link=Robert Holmes (scriptwriter) |first2=Barry (producer) |last2=Letts |author-link2=Barry Letts |network=[[BBC]] |station=[[BBC1]] |date=2–23 January 1971 }}</ref> the [[Third Doctor]] fails to recognise [[The Master (Doctor Who)|The Master]]'s voice, when the Master speaks to him on a telephone.
* In ''[[Planet of the Spiders]]'',<ref name="Planet of the Spiders">{{cite serial |title=[[Planet of the Spiders]] |series=Doctor Who |series-link=Doctor Who |first=Robert (writer) |last=Sloman |author-link=Robert Sloman |first2=Barry (director) |last2=Letts |author-link2=Barry Letts |network=[[BBC]] |station=[[BBC1]] |date=4 May – 8 June 1974 }}</ref> the [[Third Doctor]] has trouble recognising his former mentor.
* In ''[[The Deadly Assassin]]'',<ref name="The Deadly Assassin"/> Announcer Runcible, an old classmate, recognises the [[Fourth Doctor]] despite his changes in appearance and mentions that the Doctor appears to have had a "face lift" since they last met.
* In ''[[The Armageddon Factor]]'',<ref name="The Armageddon Factor">{{cite serial |title=[[The Armageddon Factor]] |series=Doctor Who |series-link=Doctor Who |first=Bob |last=Baker |author-link=Bob Baker (scriptwriter) |first2=Dave (writers) |last2=Martin |author-link2=Dave Martin (screenwriter) |first3=Michael (director) |last3=Hayes |author-link3=Michael Hayes (director) |network=[[BBC]] |station=[[BBC1]] |date=20 January – 24 February 1979 }}</ref> Drax, another alumnus immediately recognises the Fourth Doctor, though the Doctor does not recognise him.
* In "[[The Five Doctors]]",<ref name="The Five Doctors">
{{cite serial | title = [[The Five Doctors]] | series = Doctor Who | series-link = Doctor Who |first=Terrance (writer) |last=Dicks |author-link=Terrance Dicks |first2=Peter (director) |last2=Moffatt |author-link2=Peter Moffatt | network = [[PBS]] | date=23 November 1983}}</ref> the First Doctor does not recognise the Fifth Doctor as himself and needs to be introduced. Likewise, the Third Doctor is unable to initially recognise the Master in his non-Gallifreyan body.
* In ''[[The Twin Dilemma]]'',<ref name="The Twin Dilemma">{{cite serial |title=[[The Twin Dilemma]] |series=Doctor Who |series-link=Doctor Who |first=Anthony (writer) |last=Steven |author-link=Anthony Steven |first2=Peter (director) |last2=Moffatt |author-link2=Peter Moffatt |network=[[BBC]] |station=[[BBC1]] |date=22–30 March 1984 }}</ref> the Doctor's old friend Azmael fails to recognise him, as the Doctor has regenerated twice since their last encounter.
* In ''[[The Two Doctors]]'',<ref name="Two Doctors"/> when the [[Sixth Doctor]] and [[Second Doctor]] first meet, they are initially quiet until they face each other and simultaneously yell at each other, each recognising immediately the other.
* In ''[[Survival (Doctor Who)|Survival]]'', the Master recognises the [[Seventh Doctor]] on sight.<ref>{{cite serial |title=[[Survival (Doctor Who)|Survival]] |series=Doctor Who |series-link=Doctor Who |first=Rona (writer) |last=Munro |author-link=Rona Munro |first2=Alan (director) |last2=Wareing |author-link2=Alan Wareing |network=[[BBC]] |station=[[BBC1]] |date=22 November – 6 December 1989 }}</ref>
* In ''[[Doctor Who (film)|Doctor Who]]'' (1996), the [[Eighth Doctor]] is unable to recognise the Master while he possesses a human body, only recognising the Master when he corrects Grace's grammar.<ref name="tv movie"/>
* In "[[Utopia (Doctor Who)|Utopia]]",<ref name="Utopia"/> the [[Tenth Doctor]] does not recognise the human form of the Master, although the Doctor did recognise him, and name him "Master", as soon as he recovered his Time Lord physiology and mind.
* In "[[The Sound of Drums]]",<ref name="Sound of Drums"/> the Doctor states that Time Lords can "always" recognise each other, although, while on Earth, the Master used satellites with a telepathic network to mask his presence from the Doctor. The Doctor in this circumstance appears to only be referring to recognition of the individual as a Time Lord, not necessarily the specific identity. However, when he sees the Master on television, he recognises him.<ref name="Sound of Drums"/>
* In "[[Time Crash]]",<ref>{{Cite episode |title=Time Crash |episode-link=Time Crash |series=Doctor Who |series-link=Doctor Who |first=Steven (writer) |last=Moffat |author-link=Steven Moffat |first2=Graeme (director) |last2=Harper |author-link2=Graeme Harper |network=[[BBC]] |station=[[BBC One]] |date=17 November 2007 }}</ref> the [[Fifth Doctor]] could not instinctively recognise that the Tenth Doctor was a Time Lord, much less one of his own later incarnations.
* In "[[The Next Doctor]]",<ref>{{Cite episode |title=The Next Doctor |episode-link=The Next Doctor |series=Doctor Who |series-link=Doctor Who |first=Russell T (writer) |last=Davies |author-link=Russell T Davies |first2=Andy (director) |last2=Goddard |author-link2=Andy Goddard |network=[[BBC]] |station=[[BBC One]] |date=25 December 2008 }}</ref> the Tenth Doctor initially seems unable to detect that the human [[Jackson Lake (Doctor Who)|Jackson Lake]], who identifies himself as the Doctor, is not actually his regenerated future self.
* In "[[The End of Time (Doctor Who)|The End of Time]]",<ref name="end of time two"/> the Doctor immediately recognises an unidentified elderly female Time Lord on sight, and also refers to the lead Time Lord by the name Rassilon (an earlier incarnation of Rassilon had appeared in "[[The Five Doctors]]"). In the context of the story, however, he may have encountered both during the Time War, though he himself has regenerated since they last saw him. Rassilon and the woman recognised the Doctor on sight as well, but the Doctor's presence, regardless of incarnation, was expected.
* In "[[The Day of the Doctor]]",<ref name="dotd"/> the [[Tenth Doctor]] appears to sceptically recognise [[Eleventh Doctor|his successor]], yet he appears to be fully convinced only after both compare their sonic screwdrivers. The [[War Doctor]], on the other hand, is initially oblivious to meet his future incarnations and mistaking them for future [[Companion (Doctor Who)|companions]] (but is later convinced otherwise after comparing their sonic screwdrivers).
* In "[[Dark Water (Doctor Who)|Dark Water]]",<ref name="dark water">{{Cite episode |title=Dark Water |episode-link=Dark Water (Doctor Who) |series=Doctor Who |series-link=Doctor Who |first=Steven (writer) |last=Moffat |author-link=Steven Moffat |first2=Rachel (director) |last2=Talalay |author-link2=Rachel Talalay |network=[[BBC]] |station=[[BBC One]] |date=1 November 2014 |series-no=8 |number=11 }}</ref> the [[Twelfth Doctor]] is unable to recognise the Master until she reveals her identity.
* In "[[Twice Upon a Time (Doctor Who)|Twice Upon A Time]]",<ref name="twice upon a time">{{Cite episode |title=Twice Upon a Time |episode-link=Twice Upon a Time (Doctor Who) |series=Doctor Who |series-link=Doctor Who |first=Steven (writer) |last=Moffat |author-link=Steven Moffat |first2=Rachel (director) |last2=Talalay |author-link2=Rachel Talalay |network=[[BBC]] |station=[[BBC One]] |date=25 December 2017 |series-no=10 |number=Special }}</ref> the [[First Doctor]] sees the [[Twelfth Doctor]] as another Time Lord come to take back his TARDIS and requires convincing as to otherwise.
*In "[[Spyfall (Doctor Who)|Spyfall]]",<ref>{{Cite web |title=BBC One - Doctor Who, Series 12, Spyfall, Part 1 |url=https://www.bbc.co.uk/programmes/m000cs1y |access-date=2022-05-06 |website=BBC |language=en-GB}}</ref> the [[Thirteenth Doctor]] is unable to recognize the Master until he reveals his identity.

In "[[The Impossible Astronaut]]",<ref>{{Cite episode |title=The Impossible Astronaut |episode-link=The Impossible Astronaut |series=Doctor Who |series-link=Doctor Who |first=Steven (writer) |last=Moffat |author-link=Steven Moffat |first2=Toby (director) |last2=Haynes |author-link2=Toby Haynes |network=[[BBC]] |station=[[BBC One]] |date=23 April 2011 |series-no=6 |number=1 }}</ref> a future version of the Eleventh Doctor is shot, causing him to begin his regeneration cycle. He is shot again before the regeneration completes, causing him to die instantly. However, in "[[The Wedding of River Song]]",<ref>{{Cite episode |title=The Wedding of River Song |episode-link=The Wedding of River Song |series=Doctor Who |series-link=Doctor Who |first=Steven (writer) |last=Moffat |author-link=Steven Moffat |first2=Jeremy (director) |last2=Webb |author-link2=Jeremy Webb |network=[[BBC]] |station=[[BBC One]] |date=1 October 2011 |series-no=6 |number=13 }}</ref> it is revealed this was a shape shifting android the Doctor used to fake his death, making this questionable.
{{cquote| It's a bit dodgy, this process, you never know what you're gonna end up with. |30px|30px| The Ninth Doctor in "[[The Parting of the Ways]]".<ref name="potw"/>}}

In cases of non-fatal injury, Time Lords who have recently regenerated can use left over cellular energy to heal and even regrow severed limbs, as seen in "[[The Christmas Invasion]]" where the Tenth Doctor regrows a hand.<ref name="Christmas Invasion"/> Also seen in "[[Journey's End (Doctor Who)|Journey's End]]", is the apparent ability to siphon off regeneration energy in order to cancel the effect of changing appearance; which requires them to have a "bio-matching receptacle" (in this case the Doctor's severed hand), which is usually impractical.<ref name="journeys"/> However, this "non-regeneration" was revealed as "counting" towards the Doctor's twelve possible regenerations during the events of "[[The Time of the Doctor]]".<ref name="totd"/><ref>{{cite web |url=http://www.tor.com/blogs/2013/11/answers-on-regeneration-steven-moffat-drops-a-bomb-about-the-doctor-who-christmas-special |title=Answers on Regeneration: Steven Moffat Drops A Bomb About the Doctor Who Christmas Special |author=Stubby the Rocket |publisher=tor.com |date=25 November 2013 |url-status=live |archive-url=https://web.archive.org/web/20131228032935/http://www.tor.com/blogs/2013/11/answers-on-regeneration-steven-moffat-drops-a-bomb-about-the-doctor-who-christmas-special |archive-date=28 December 2013  }}</ref>

In "The End of Time", the [[Tenth Doctor]] was able to postpone his regeneration long enough so that he could travel in time and space to see his past companions for one last time before he regenerated. The [[Fifth Doctor]] had also shown a similar ability in ''[[The Caves of Androzani]]'', fighting off the effects of an impending regeneration so he can return to Androzani Minor to save his companion Peri.

Time Lords appear to have the ability to stay conscious for moments after events that would outright kill other lifeforms instantly, giving them the opportunity to regenerate. This is seen in ''[[Logopolis]]'' (fall from a great height), and ''The Caves of Androzani'' (fatal disease). In both "[[The Stolen Earth]]" and "[[The Big Bang (Doctor Who)|The Big Bang]]", the Doctor is shot by a Dalek's energy weapon, which has almost always been shown to instantly kill any other lifeform, yet is still conscious and able to return to return to the TARDIS and Pandorica respectively.

In ''[[Death of the Doctor]]'', the Eleventh Doctor responds to a question from [[Clyde Langer]] by saying he can regenerate "507" times.<ref name="NotSerious" /> Early news reports, before the episode was broadcast, suggested he would say there is no limit to the number of regenerations.<ref>{{cite news |url=https://www.theguardian.com/tv-and-radio/2010/oct/12/doctor-who-immortal-reveals-bbc |title=Doctor Who is now immortal, reveals the BBC |author=Emily Barr |newspaper=The Guardian |date=13 October 2010 |access-date=13 October 2010 |url-status=live |archive-url=https://web.archive.org/web/20130805113305/http://www.theguardian.com/tv-and-radio/2010/oct/12/doctor-who-immortal-reveals-bbc |archive-date=5 August 2013  }}</ref> Writer [[Russell T Davies]] stated in an interview with ''[[SFX (magazine)|SFX]]'' that the line was not intended to be taken seriously and is instead a commentary. He said that the "thirteen lives" rule was too deeply entrenched in the viewer consciousness for his throwaway line to affect it.<ref name="NotSerious">{{cite web |url=http://www.sfx.co.uk/2010/10/26/interview-russell-t-davies-talks-about-that-sarah-jane-adventures-line/ |title=INTERVIEW Russell T Davies talks about THAT Sarah Jane Adventures line |work=SFX |date=26 October 2010 |access-date=17 September 2013 |url-status=live |archive-url=https://web.archive.org/web/20130927082428/http://www.sfx.co.uk/2010/10/26/interview-russell-t-davies-talks-about-that-sarah-jane-adventures-line/ |archive-date=27 September 2013  }}</ref>

It is revealed in "[[The Time of the Doctor]]" that this was in fact false and that due to his various regenerations, the [[Eleventh Doctor]] was in fact his last incarnation. However, the Time Lords intervened through a crack in time to grant him a full new regeneration cycle. The revelation in 2020's "[[The Timeless Children]]" that The Doctor is, in fact, not Gallifreyan and instead had their DNA used to give Gallifreyans the ability to regenerate, calls into doubt whether or not the Doctor does in fact have a limit to their regenerations, or if they merely believed they did due to all other Time Lords being limited.

In "[[The Giggle]]", the Fourteenth Doctor, after being mortally wounded with a laser cannon by the Toymaker, undergoes 'bi-generation', a process that causes his next incarnation to split off into a separate entity, the Fifteenth Doctor, while healing the Fourteenth Doctor's injuries. This process is witnessed again in "[[The Interstellar Song Contest]]" when Mrs Flood, revealed to be The Rani, undergoes bi-generation after being revived.