The Time Force was a destructive mass of temporal particles that was unleashed in the aftermath of the Flux, which came to be known as the Great Disruption. It was the natural result of time running wild and was caused by the breaking of four of the Mouri, who maintained the flow of time from the Temple of Atropos on the planet Time. (TV: Once, Upon Time) Two were broken by the Flux according to the Priest Triangles, whereas a further two were disintegrated by the Ravagers Swarm and Azure to be replaced with Yasmin Khan and Inston-Vee Vinder. (TV: War of the Sontarans)
Much like the Flux, the Time Force destroyed all it came into contact with. The Time Force appeared blue when dormant, but would turn purple when active. It was encountered by Bel on a Dalek-invaded planet, and by Dan Lewis during a time storm in his time stream inside the tunnels dug out by Joseph Williamson in 1820 Liverpool.
Although the Mouri were replaced in an attempt to undo the damage done to time, at first temporarily with Yaz, Vinder, Dan and the Thirteenth Doctor, and then permanently with four Mouri hidden inside a Passenger form, it was too late as the Ravagers had already harnessed particles of the Time Force for their own goals. (TV: Once, Upon Time)
The Time Force, in conjunction with spatial energy harvested from lifeforms trapped within the Ravagers' Passengers, (TV: Survivors of the Flux) as well as the psychic link that once existed between the Old Swarm and the Fugitive Doctor and had been reactivated between the New Swarm and the Thirteenth Doctor, (TV: The Halloween Apocalypse) allowed Swarm to build a psycho-temporal bridge to the Doctor, which he and his sister used to cross into Division Control, situated in the Void between Universes One and Two, where the Doctor had been transported to by Tecteun. (TV: Survivors of the Flux)
Swarm and Azure sought to give the Doctor as a sacrifice to their "saviour", Time, an Eternal and the embodiment of time worshipped by the Ravagers. Time, who had been imprisoned in the Temple of Atropos since the Mouri were instated, manifested from active particles of the Time Force to scorn the Ravagers for their failure in freeing Time from Atropos, and to inform them that the final Flux event they had launched from the Division's base had been thwarted. Time punished the Ravagers, destroying them in the process, although Azure viewed it as a form of ascension. When left face to face with the Doctor, Time warned the Doctor that her time was ending, and that no regeneration or life could last forever. It reunited the Doctor, who had been fragmented into three splinters across spacetime, and returned her to her TARDIS. (TV: The Vanquishers)