Time sensitivity

Time Sense, (GAME: Lost in Time) time sensitivity or time awareness, also referred to as witch-blood among the lesser species, was an ability possessed by individuals or species that allowed them to naturally perceive and influence the ebb and flow of time. (PROSE: The Book of the War) With training, the ability could be tuned to build complicated temporal maps, tracing the histories of multiple people to triangulate intersections. (PROSE: Warring States) When partnered with a time channeller, a time sensitive could travel along timelines. (PROSE: The Winning Side, Peculiar Lives, et al)

Time sensitives were able to see people's entire timelines by touching them, or sometimes seeing a "time snake" around their body. (PROSE: The Tunnel at the End of the Light, The Severed Man) They were also able to detect "pressure points" in history. Changes made at those points would ripple both backwards and forwards through history in a way that was different from cause and effect. (PROSE: Head of State)

According to the Shift, "almost all" time-sensitives either belonged to the Great Houses or the Enemy. (PROSE: Head of State)

Time Lords
Time Lords were naturally time-sensitive (AUDIO: Prisoners of Fate, PROSE: The Book of the War) thanks to their symbiotic nuclei. (GAME: Lost in Time) In fact, they should have been the only time sensitives in existence. It was speculated that when individual members or bloodlines in "lesser species" exhibited time-active biodata, this was because of hybridisation with a member of the Great Houses (or one of their augmented regen-inf soldiers) somewhere in their family lineage. (PROSE: The Book of the War)

Time Lords could detect time sensitivity in others easily, (AUDIO: 1963: Fanfare for the Common Men) though, as Time Lords tended to be rigid, unemotional, and certain where time-sensitives were fluid, volatile, and transient, the two groups did not tend to mix well. (PROSE: The Parliament of Rats)

According to the Eleventh Doctor, his people developed their special relationship with time gradually over generations, due to their exposure to the Untempered Schism. (TV: A Good Man Goes to War) In Gallifrey's ancient history, during Rassilon's original Presidency, when Type 1 TARDISes were just beginning to be experimented with, the growing numbers of "Evolved Time Sensitives" were tracked with great interest among the Gallifreyan population. When a modern Time Lord, the Eleventh Doctor himself, ended up in this period of Gallifreyan history and came face-to-face with Rassilon, he was recognised as a "Level 7 Evolved Time Sensitive", which was also Rassilon himself's own classification. (COMIC: The Lost Dimension)

Humans
Time sensitives could also manifest amongst human populations. (PROSE: The Cabinet of Light, Walking to Babylon, Camera Obscura, The Parliament of Rats; TV: Human Nature / The Family of Blood)

In some cases, this was due to the presence of a member of the Great Houses somewhere in their bloodline; (PROSE: The Book of the War) even without conventional interbreeding, contact with a Time Lord or TARDIS could influence humans and their descendants in ths way. The Seventh Doctor worried that he had affected his companions more deeply than he would like to admit, saying that Timothy Dean introduced unthinkable quantitites of Time Lord DNA to the human species and that Bernice's children would have a bit of Time Lord genetics. Other companions he worried about in this way were Chris, Ancelyn, and Jo. (PROSE: Christmas on a Rational Planet) River Song also gained biological qualities similar to a Time Lord's as a result of having been conceived by Amy Pond and Rory Williams while inside the Doctor's TARDIS in-flight in the Time Vortex. (TV: A Good Man Goes to War)

Despite time sensitive individuals' ability to naturally communicate with the loa, Faction Paradox was cautious about initiating members with witch-blood, since it was far harder to sculpt their biodata to the Faction's requirements. However, Cousins Octavia (PROSE: The Book of the War) and Justine both possessed witchblood. (AUDIO: The Eleven Day Empire) In Mujun: The Ghost Kingdom, Awaremi recognised a similarity between her bloodline and Kodomo Kami's witch-blood. (PROSE: The Book of the War)

While most timeships were wary of having the "wild" biodata of non-Homeworlder time sensitives inside of them, Compassion actually used an elaborate time-loop to repeatedly harvest from Cousin Octavia and Liu Hui Ying, both of whom had witchblood. (PROSE: Warring States)

Sabbath Dei acquired time-awareness through the use of rituals. (AUDIO: Sabbath Dei)

The Gestalt granted their hosts temporal sensitivity even if they had not previously possessed it, including humans such as Kady Williams. (PROSE: Ring Theory)

Other species
Other time-sensitive species included Tharils, Jagaroth, and Xeraphin. (AUDIO: Prisoners of Fate) The Tharils, in particular, were highly prized by humans for their ability to navigate timelines. Dwarf star alloy was the only substance that could hold time sensitives like Tharils. (TV: Warriors' Gate)

The Unnoticed used time sensitives to alert them of the presence of time travellers or planets with time travel capability. (PROSE: The Book of the Still)

Maxie's kind were known by Giles to have a "special relationship" to time. (HOMEVID: Daylight Savings)

Eve belonged to a time-sensitive species that was deemed a threat during the Last Great Time War and exterminated. (TV: The Mad Woman in the Attic)

According to The Dark Times Times, written by River Song, the Dalek Empire's Time Squad was made up of Time-Sensitive Daleks. (PROSE: The Guide to the Dark Times)