After bi-generation, the Fifteenth Doctor helped the Fourteenth banish the Toymaker and encouraged him to recover with the Noble family. Freed from his past baggage, he travelled with new optimism—though he knew the Toymaker’s legions were coming. He met Ruby Sunday while stopping child-eating goblins, and she joined him. Their travels were haunted by the mystery of Ruby’s mother, shown through strange snowfalls and a recurring woman. This collided with Sutekh’s return: Sutekh hijacked the TARDIS to spread Death Dust across the Doctor’s past. The Doctor destroyed him with the Time Vortex, reversed the annihilation, and found Ruby’s birth mother—an ordinary woman made significant only by their obsession. Ruby stayed to know her family. Personality: fun-loving, optimistic, adventurous, amazed by the universe, prefers blending in, comforts others, and lives in the moment for himself and fallen friends.

Ruby Sunday was believed to have been born around 2 PM on 24 December 2004. Her parents were Louise Miller and William Benjamin Garnet, both fifteen when Louise became pregnant. Louise abandoned Ruby outside the church on Ruby Road in the snow, likely to protect her from her abusive stepfather. The Fifteenth Doctor travelled back from 2023 to stop the Goblins from stealing and eating baby Ruby, restoring the original timeline. Ruby was found by the vicar and named after the road—a name Louise had chosen, though Ruby thought social workers or paramedics had named her. On 1 December 2023, Ruby appeared on Davina McCall’s show to find her birth family. Carla had told her not to let anyone else tell her story. Filming was disrupted by Goblin bad luck, and Ruby suffered a run of misfortune. On 22 December her keyboard failed during a gig; on 23 December the Doctor caught her drink at a club. On Christmas Eve, her nineteenth birthday, Carla was fostering baby Lulubelle. Davina called to say Ruby’s family could not be traced. Goblins then kidnapped Lulubelle. Ruby chased them to the roof and grabbed their ladder; the Doctor joined her. They were captured, but the Doctor explained the Goblins were time riders creating coincidences to feed Lulubelle to the Goblin King. They escaped, saved Lulubelle, and returned her before Carla came home. The Goblins then went back to 2004 to steal Ruby as a baby, but the Doctor saved her and killed the Goblin King, causing them to fade. Ruby realised he was a time traveller and left with him in the TARDIS. Ruby was bubbly, energetic, adventurous, and comfortable calling herself a “foundling,” but she still wanted the truth about her birth parents. She loved Carla deeply, felt stranded in London, and wanted her birth mother to know she enjoyed her life. When she finally met Louise, she understood and forgave her; Louise had feared Ruby’s anger. Ruby grew very close to the Doctor, risking her life for him. She was disgusted by Finetime’s bigotry and compassion toward lonely babies and Emily Beckett, and protective of Carla’s foster children, especially Lulubelle. Music was central to her: keyboard, band, songwriting, Regency-era music, and dancing.

Kate Lethbridge-Stewart is the commander-in-chief of the Unified Intelligence Taskforce (UNIT) and the daughter of the late Brigadier Alistair Gordon Lethbridge-Stewart, the Doctor's longtime friend. She first appeared in the 1995 spin-off Downtime, portrayed by Beverley Cressman, before being reintroduced to Doctor Who in 2012's "The Power of Three," played by Jemma Redgrave. Kate grew up unaware of her father's extraterrestrial work, believing he had an ordinary military job. She blamed his absences for her parents' separation. Years later, after fighting the Great Intelligence alongside her father, she investigated UNIT and joined the organization, rising to its top position. She initially dropped "Lethbridge" from her surname to avoid any favours, rising through the ranks as "Kate Stewart". As UNIT's leader, Kate championed a science-first approach over traditional military tactics, recalling her father's advice that "science leads". She met the Eleventh Doctor during the Shakri cube invasion and rekindled UNIT's alliance with him, respecting her father's legacy while forging her own bond with the Time Lord. She has since appeared alongside multiple incarnations, including the War, Tenth, Eleventh, Twelfth, Thirteenth, Fourteenth, and Fifteenth Doctors. Kate is practical, disciplined, and determined, with a dry sense of humour. She shares her father's loyalty and faith in the Doctor, but her approach differs markedly—where his tactics were military, hers are scientific. She is willing to make painful decisions when necessary; during the Zygon invasion, she threatened to self-destruct the Black Archive, destroying London, rather than let alien weaponry fall into the wrong hands. Despite moments of doubt, she has never given in to despair, embodying her father's resilience. She was present at the Toymaker's crisis, witnessing the Fourteenth and Fifteenth Doctors' bi-generation.