Written by Chris Chibnall
"I will kill every last Sontaran!"
| Episode Title | Premiere Date |
| The Vanquishers | 05/12/2021 |
In the final epic chapter in the story of the Flux, all hope is lost. The forces of darkness are in control. But when the monsters have won, who can you count upon to save the universe?
| Character | Cast |
| The Doctor | Jodie Whittaker |
| Mandip Gill | Mandip Gill |
| Dan Lewis | John Bishop |
| Professor Jericho | Kevin McNally |
| Azure | Rochenda Sandall |
| Swarm | Sam Spurell |
| Bel | Thaddea Graham |
| Joseph Williamson | Steve Oram |
| Kate Stewart | Jemma Redgrave |
| Grand Serpent | Craig Parkinson |
| Karvanista | Craige Els |
| Sontaran Commander Stenck | Jonathan Watson |
| Senstarg / Shallo / Kragar | Dan Starkey |
| Claire Brown | Annabel Scholey |
| Vinder | Jacob Anderson |
| Diane | Nadia Albina |
| Voice of the Ood | Silas Carson |
| Dalek Operator | Nicholas Pegg |
| Dalek Operator | Barnaby Edwards |
| Stevie | Sonny Walker |
| Voice of the Daleks/Cybermen | Nicholas Briggs |
| Ood | Simon Carew |
| Passenger | Jonny Mathers |
| Role | Crew |
| Writer | Chris Chibnall |
| Director | Azhur Saleem |
| Executive Producer | Matt Strevens |
| Executive Producer | Chris Chibnall |
