| “ | Surrender to death. | „ |
| ~ The Grand Serpent to the Doctor |
The Grand Serpent is the corrupt ruler of an interstellar empire. He serves as the overarching antagonist in Series 11 and a major antagonist in Series 13 of Doctor Who. He is the one reponsible for getting Vinder exiled to Outpost Rose, and would later interfere in the creation of UNIT.
He was portrayed by Craig Parkinson, who also play Matthew "Dot" Cottan in Line of Duty.
Biography
Past
As revealed in The Vanquishers, the Grand Serpent came from a binary demi-species, a symbiotic species divided into a humanoid and serpent form, and the more intelligent humanoid form was able to control the deadly serpent. The Grand Serpent went into politics, and at one point ruled a vast empire, which presumably when he dubbed himself by his title. He was criticised by Frey Sampor, whom he was determined to get back at.
Once, Upon Time
As recalled by his body guard, Inston-Vee Vinder, the Grand Serpent met a species called the Alforia to discuss terms to shelter them, in return for them providing "food and safety" for generations. After Vinder spoke out of line, he dressed him down and ordered him to be silent from thereon in. Once the official meeting was concluded, he ordered Vinder to cease recording and then demanded the Alforia hand over five dissidents being sheltered in their territory to face trial, and for another four, all relatives of his critic Frey Sampor, to suffer a fatal accident. Vinder reported the incident, resulting in him being reassigned to Observation Outpost Rose.
At some point, as revealed in The Vanquishers, despite his attempts to silence his critics, the Grand Serpent was eventually overthrown and was exiled from his empire.
Survivors of the Flux
At some point after his exile, the Grand Serpent formed an alliance with the Sontarans. To allow them the opportunity to invade Earth, the Grand Serpent travelled back to 1958. After taking up the name Prentis, he befriended General Farquhar, telling him that he had experience in threats from outer space, and agreed in helping him to establish UNIT, a United Nations task force for combatting extraterrestrial threats, in order to better infiltrate Earth's defences.
In 1967, General Farquhar invented technology that would allow him to test whether or not somebody was human and insisted that everybody in UNIT submit to testing to guard against infiltration. Despite his protests, the Grand Serpent was scanned by the machine and flagged as non-human. He then revealed his true self by summoning a snake-like creature which killed Farquhar in order to conceal his identity. He later used the same creature to kill Millington, the head of the UNIT Oversight Committee, allowing him to take his job and suspend UNIT operations under the pretext of lack of funds due to Britain leaving the European Union. When UNIT commander Kate Stewart discovered his true nature and threatened to expose him, he bombed her house and forced her to go into hiding.
In 2021, the Grand Serpent ordered UNIT to lower Earth's defence shields, allowing a Sontaran invasion force led by Commander Stenck to land and occupy the planet.
The Vanquishers
After the Sontaran occupation, the Grand Serpent resided at the Sontaran's Psychic Command Centre in Chile, where the Sontarans were conducting psychic experiments to locate the final Flux event as part of a wider plan to lure in and destroy all enemy races under the guise of an alliance. When a splinter of the Thirteenth Doctor and Karvanista were captured while infiltrating the base, Stenck and the Grand Serpent interrogated them and taunted Karvanista by revealing that the rest of his species had been wiped out by the Sontarans. The Grand Serpent then trapped the Doctor in an interrogation beam and questioned her. He attempted to kill her with his snake creature but failed because she was not fully there. Another of the Doctor's splinters soon arrived and trapped the Grand Serpent in his interrogation beam before the two Doctors escaped.
After escaping from the interrogation beam, the Grand Serpent scanned all artron energy readings to track down the Doctor, which led him to Kate Stewart. He used his snake creature to interrogate and kill a contact of Kate's in order to discern her location at the Williamson Tunnels beneath Liverpool. However, when he arrived he was ambushed by Vinder, who had been helping the Doctor. The Grand Serpent was held at gunpoint by Vinder, who he did not remember, and was forced to go through one of the interdimensional doors in the tunnels, leaving him stranded on an asteroid.
