Doctors
The Ninth Doctor
- Voiced by Mathew UrchPhysically based on Henry Lloyd-Hughes
- Affectionate Nickname: Calls Whitney "glamorous assistant". The producers made sure this died a quiet death when the Doctor regenerated.
- Experienced Protagonist: Clearly. This is the Doctor - of course he knows the ins and outs of interdimensional travel, when the Sea Devils and Silurians lived, and more.
- O.O.C. Is Serious Business: This is what was intended at the end of Calladra. It didn't come off that way due to the writer's inexperience at portraying this.
The Tenth Doctor
- Voiced by Scott D. Harris
- The Determinator: Aside from his Heroic BSOD (see below), he's generally this after his Establishing Character Moment at the end of The Wooden Planet.
- Dreadful Musician: Can't carry a tune in a bucket, as demonstrated by his performance of "Les Poissons" in The Ride of the Headless Horseman.
- Experienced Protagonist: Demonstrates an understanding of Indian history, encyclopedic knowledge of the Krynoid life-cycle, and a solid repertoire of songs from Styx to Tom Lehrer (if only he could sing).
- Heroic BSoD: Has a brief one after losing the TARDIS, Whitney, and K-9 in The Ride of the Headless Horseman.
- Loud of War: Fending off the Headless Horseman with an air horn and megaphone.
- In the original draft, the Doctor actually defeated the Horseman in the end by singing an off-key rendition of Dean Martin's "Ain't That a Kick in the Head" into the megaphone. Scott D. Harris requested that this be changed to 'spare the audience'.
Companions
Whitney Anderson
- Voiced by April SadowskiPhysically based on Carey Mulligan
- Affectionate Nickname: See above.
- Big Sister Instinct: Seems to have a bit of one with Zacharias - at the very least, she does see him as something of a little brother, moreso alongside the more brotherly Ninth Doctor.
- Defiant Captive: On the rare occasion she is captured, then she fits this trope to a tee.
- "Once I get untied, you're in for a world of hurt, Solozano. You hear me? You'll pay for what you did to the Doctor. You, and your master!"
Zacharias Cobb
- Voiced by Caith Donovan and Nick Cochran (Calladra only)Physically based on Dylan O'Brien
- Distressed Dude: Zacharias is the first to bemoan the crew's seemingly imminent deaths if they're captured, as seen in Las Pinturas Negras and Flux Time.
- Non-Action Guy: If you're looking for a courageous fighter, then look elsewhere - Zacharias would typically rather run than use fisticuffs.
- Non-Action Snarker: And how!
- "Anything else you want to tell us you're certain of, Lianne, so we can assume the opposite?"
K-9
- Voiced by Matt "Timey" Clarke (S1, except The Ride of the Headless Horseman) and Christopher Thomson (S2, plus Headless Horseman)Redesign by Rory McLeish
- Deadpan Snarker: Not as much as in the main show, but he has his moments.
- Legacy Character: He's technically K-9 Mk. V.
- Pint-Sized Powerhouse: His laser is very powerful, as demonstrated in The Wooden Planet.
- Robot Dog: Well, seeing as he's a supercomputer shaped like a metal dog...
- Zeerust: While more modern-looking than previous models, he's still rather outdated-looking.
Allies
The Ride of the Headless Horseman
The Hessian
- Voiced by Jason R. Wallace and Rachel RiemkePhysically based on Henry Cavill (for the Wallace incarnation)
- Genius Bruiser: Before he loses his body to the Horseman.