Doctor Who's next enemy is death itself. The Doctor is the ultimate adventurer. He - or, in her current incarnation, she - travels through time and space, attempting to do good and fight against the most dangerous foes in the cosmos. As the Second Doctor once declared, "There are some corners of the universe which have bred the most terrible things. Things which act against everything we believe in. They must be fought."
But Doctor Who is far more just a television series; rather, it has a rich history of transmedia. And the franchise is launching its boldest transmedia initiative, the "Time Lord Victorious," which will see various incarnations of the Doctor travel back to the Dark Times at the beginning of the universe. There, the Doctors will be faced with some very familiar faces - the likes of the Racnoss and Daemons, the Great Vampires, and the Osirans - as well as a terrifying threat. The Doctor is about to face death itself.
The Doctor Who Annual 2021 introduces an alien race called the Kotturuh, and it seems they are the ones who introduced death into the universe. It seems death was unknown at the beginning of time, and consequently, the first living creatures were all immortals. And then the Kotturuh arrived, and they learned they had the power to take death wherever they went. The Kotturuh consider it their mission to bring order to the cosmos, and they achieve this by visiting a world and allocating a lifespan to the beings they found there. Some creatures were allowed to go on for thousands of years, and others are obliterated on the spot.
The Eternals fled from the Koturruh, while the Racnoss went into hibernation at the center of the Earth in order to survive the Kotturuh's wrath. Some other races attempted to fight them, including the Daemons, who were almost wiped out. But synopses for the upcoming "Time Lord Victorious" novels suggest at least one of the Doctors will team up with the army opposing the Kotturuh - and that's a new random element sure to change history. The comics have already teased that at least one race who were supposed to die in the Dark Times, the Hond, have now survived until the present - and are attempting to exterminate the Daleks. The Daleks have recruited their last protector, David Tennant's Tenth Doctor.
Doctor Who is clearly drawing inspiration from religions like Christianity, which maintain a good God originally created a world without death, and that death should be seen as an unwelcome intruder in creation. And now the Doctor is going up against the source of death itself - the greatest threat he has ever faced.