Fifteenth Doctor

The Fifteenth Doctor was an incarnation of the Doctor and the successor to the Fourteenth Doctor. He had at least one adventure involving "Ruby S". (PROSE: )

Post-regeneration
After an adventure involving "Ruby S", (PROSE: ) the Doctor decided that the attire of his previous incarnation "[wouldn't] do", choosing his new clothing in the TARDIS, sturdy boots and a new hat being amongst the items chosen. (POEM: ) He also wrote in his diary about his adventure, quoting himself saying "what the h[...] here?" (PROSE: )

The Fifteenth Doctor, early on, was aware a new chapter in his life was beginning, as he had a new face, friends and adventures to go on. He was aware that he had new threats and enemies to face, and that they had "no idea what [they'd] let themselves in for." (PROSE: )

Further adventures
The Fifteenth Doctor arrived outside the Time Bubble containing Nora Wicker's home on 16 December 2033. The Eleventh Doctor had secured his help after deciding to free Nora following the forty-six years she spent inadvertently trapped inside, each day looping over and over, as the Eleventh Doctor miscalculated the size of the bubble when he erected it to contain the seed of the World Tree that had landed in her garden on 19 August 1987.

After exiting his TARDIS, the Fifteenth Doctor waved to Nora and the Eleventh Doctor, then readied himself to use his sonic screwdriver at the same time as the Eleventh Doctor to produce a precise frequency to create a crack in the bubble. However, at the last possible moment, Nora confided to the Eleventh Doctor that she wanted to remain in the bubble to look after the tree, distracting the Eleventh Doctor and causing the sync to fail. The Fifteenth Doctor lowered his screwdriver and returned to the TARDIS, planning to return the next day, but ultimately did not as to respect Nora's wishes. (AUDIO: )

At some point prior to 5 March 2005, the Doctor was photographed. This photo would later be in the possession of Clive Finch. (PROSE: )

The Daft Dimension
In the Daft Dimension, the "new Doctor", as mentioned by one fan, was among the exciting new developments of Doctor Who. (COMIC: )

Appearance
The Doctor had a "nice" new face which fitted well into place, with his hair being short and his nose being just right. His legs were firm and his eyes were bright.

Wearing the clothes of their predecessor for a short time and believing them to be "off-the-peg", the Doctor first pondered on wearing a frilly shirt and a scarf before deciding they were "over them" and "a touch too soon" respectively. The Doctor finally chose some sturdy boots, believing them to be handy for the Moon and a "nice" new hat. (POEM: )

Personality
The Fifteenth Doctor displayed an optimistic and adventurous outlook towards the future. (PROSE: )

The Fourteenth Doctor?
The BBC announcement revealing Ncuti Gatwa's casting as the Doctor was worded ambiguously, with Gatwa's Doctor only described as "the new Doctor"; he was not explicitly stated to be the Fourteenth Doctor, or the successor to Jodie Whittaker's Thirteenth Doctor. Nevertheless, numerous news outlets presumed that Gatwa's incarnation would be the Fourteenth Doctor and incorrectly reported as such.

However, Whittaker's final episode, The Power of the Doctor, depicted the Thirteenth Doctor regenerating into a new incarnation once again portrayed by Tenth Doctor actor David Tennant. After Power of the Doctor's broadcast, Russell T Davies confirmed that Tennant's new incarnation was the Fourteenth Doctor, and that Gatwa's would follow as the Fifteenth.

The first black Doctor?
The Fifteenth Doctor was the first "main" ordinal incarnation of the Doctor in the programme's history to be played by a black man, namely Rwandan-Scottish actor Ncuti Gatwa; however, other black Doctors have previously appeared in the Doctor Who universe.

Comedian Lenny Henry was the very first non-white actor to portray the Doctor; in an untitled skit from an episode of The Lenny Henry Show broadcast on 3 October 1985, Henry portrayed a parodical Seventh Doctor. Upon Gatwa's casting in 2022, Henry praised the development, noting "a lot of black fans have been looking at our watches for a while! More power to Russell T Davies." While Henry's incarnation is not considered part of Doctor Who's "main continuity", it would take thirty-three more years for another black Doctor to appear in any media.

Russell T Davies's novelisation of Rose, released on 5 April 2018, featured a photograph in conspiracy theorist Clive Finch's possession that showed a tall, bald, black female Doctor who wielded a flaming sword.

The 2020 episode Fugitive of the Judoon introduced the "Fugitive Doctor", a mysterious, previously unknown incarnation of the Doctor portrayed by BAME actor Jo Martin. This unseen incarnation, a predecessor to the First Doctor, joins the ranks of the eight other "pre-Hartnell" Doctors introduced in the 1976 serial The Brain of Morbius. Within the same series as Fugitive, several of the Timeless Children — seven youthful incarnations of the Doctor — were played by BAME child actors, most notably including the first.

In addition, various "bodyswaps" have been depicted wherein the Doctor temporarily possesses the body of a BAME individual, such as Daniel Anthony's Clyde Langer being possessed by the Eleventh Doctor in Death of the Doctor, and Damian Lynch's Benjamin Chikoto, who the Third Doctor uses as a means to communicate in Ghost in the Machine.

At the time of production for Silence in the Library and Forest of the Dead, Steven Moffat secretly intended Doctor Moon to be a future Doctor, meaning that Colin Salmon would have been the first BAME actor to portray a main ordinal Doctor, although this was never revealed in any later work of fiction. In Showrunner Showdown in 2020, Moffat commented that he thought a version of this idea could still work and Russell T Davies revealed that he always thought of the character as the Doctor while watching the episode.

A queer incarnation?
Gatwa has the distinction of being the first openly queer actor to portray a mainline ordinal incarnation of the Doctor; queer actor Mark Gatiss portrayed an non-ordinal Doctor in the parody skit The Web of Caves, while Geoffrey Bayldon portrayed an alternate universe Doctor in the Doctor Who Unbound audio series.

Though it remains to be seen if the Fifteenth Doctor himself is queer, co-star Neil Patrick Harris has described Gatwa as "the first gay Doctor". The question of which incarnation constitutes the "first gay Doctor" is a matter of debate; the friendship between the Thirteenth Doctor and Yasmin Khan became romantically tinged towards the end of the Chris Chibnall era, though the pair never explicitly expressed their attraction to one another, and the Eighth Doctor was implied to be non-heterosexual in the Eighth Doctor Adventures series of novels. Furthermore, many stories released in the 1990s and beyond reiterate that the Time Lords’ concept of gender differs to that of humanity.

Appearances prior to his first full television story
Continuing the trend set by the Thirteenth and Fourteenth Doctors, the Fifteenth Doctor appeared multiple times in expanded media before his television debut.
 * Interestingly, the Fifteenth Doctor's first appearance was technically before the Thirteenth Doctor's television debut in ; he appeared implicitly in the 2017 poem, as an ambiguous then-future Doctor with short hair, wherein this Doctor rummaged through a chest looking for a new costume, settling on a hat and boots. As revealed on the Official Doctor Who Twitter account, the Fifteenth Doctor does indeed have very short hair, wears a stetson, and boots.
 * His second appearance was also implicitly in the audio drama, which, while ambiguous as to which future Doctor appeared in it, Nick Slawicz, the story's author, confirmed that the Fifteenth Doctor was indeed the Doctor present in that story. Slawicz further explained that he didn’t consciously make the future Doctor ambiguous as the costume reveal hadn’t been revealed at the time of the final draft of the story.
 * The pink-painted TARDIS that appeared as part of a cross-promotion exhibit with the 2023 film Barbie could be argued to be that of the Fifteenth Doctor, owing to the fact that Ncuti Gatwa also played a Ken in the film; Russell T Davies claimed the exhibit depicted genuine in-universe events.
 * The first explicit appearance of the Fifteenth Doctor was in the short story, which depicted an obscured diary entry of the Doctor written shortly after his first adventure.
 * The Fifteenth Doctor's entry in the encyclopaedia was styled as an inner monologue of the Doctor, wherein he reflected on the new friends and foes in his life.
 * Although not an appearance of the Fifteenth Doctor per se, Ncuti Gatwa appeared in-costume as the Doctor in a version of broadcast on BBC Four on 23 November 2023 as part of William Hartnell's (David Bradley) premonition of the future of Doctor Who, replacing Matt Smith's role from the original version broadcast in 2013.
 * In the illustrated edition of of  released on 23 November 2023, photographs of the Fourteenth and Fifteenth Doctors were added to Clive Finch's collection of photographs of the Doctor.

Costume

 * Ncuti Gatwa had a role in the costume chosen for the Fifteenth Doctor.

Other matters

 * A clip of the Fifteenth Doctor was used in the Whoniverse ident released on 31 October 2023.
 * A version of Lee Sullivan's The Usual Suspects? art piece including the Fifteenth Doctor was released on 21 October 2023 for the Adventures in Time and Space – 60 Years of Doctor Who Art Exhibition exhibition held at Weston Museum, although there is no indication that this version of the artwork is licensed, although versions released earlier were.
 * Various pieces of fan art of the Fifteenth Doctor and Ruby were shared by the Official Doctor Who Twitter account under the #FanArtFriday and #DWFanArt hashtags.