Time sensitivity

Time sensitivity or time awareness, also known 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 channeler, a time sensitive could travel along timelines. (PROSE: The Winning Side, Peculiar Lives, et al)

Time Lords were naturally time sensitive; (AUDIO: Prisoners of Fate, PROSE: The Book of the War) in fact, they should have been the only time sensitives in existence. However, time-active biodata appeared in many other species, inspiring theories that the hybrid biodata was introduced by a single ancestor or descendant. (PROSE: The Book of the War) Time Lords could detect time sensitivity in others easily. (AUDIO: 1963: Fanfare for the Common Men)

According to Rassilon, the Eleventh Doctor was a "Level 7 Evolved Time Sensitive" just like himself, and wondered how he was missed in the last census. (COMIC: The Lost Dimension)

In humanity
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) 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)

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)

Other species
Other time-sensitive species included Tharils, Jagaroth, and Xeraphin. (AUDIO: Prisoners of Fate)

The Tharils 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)

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)