Susan Triad

Played by Susan Twist

"This is when it changes. This is when the whole world changes!” 

An IT genius from a humble background, Susan’s sudden rise to prominence rings alarm bells with both UNIT and the Doctor, who had witnessed her throughout space and time in various guises. Although she has been experiencing strange dreams, Susan is unaware that she is under the control of Sutekh. On his defeat, she retains her original pleasant personality.  

Character Bio

The head of S Triad Technology, Susan Triad is an ordinary human whose technology company grew from humble beginnings to worldwide coverage and monumental importance due to her entrepreneurial skill, genius, and good nature. Sue (as she prefers to be called) was due to release her technology for free to the entire world, but has been troubled by strange dreams: of being a 17th century maid, a tea lady, a number of aliens, and even an ambulance. 

At first, the Fifteenth Doctor believes she might be his granddaughter, Susan, due to their sharing the same name and her full name, S. Triad, being an anagram of TARDIS. This, combined with Sue’s prominence, was enough to bring her to the notice of UNIT even before the Doctor had arrived to investigate her. Mel Bush was sent in undercover to discover the truth though only uncovered that S Triad was “really nice”. In fact, Sue’s good nature and seeming connection to the Doctor was a trap set by Sutekh the God of Death. 

S Triad had been created by Sutekh, using the power of his own mind and the TARDIS’ perception filter. Having clung to the TARDIS for thousands of years, Sutekh was able to use its capabilities to retroactively create a backstory and persona for Susan. As Susan begins her announcement to the world, she suddenly collapses and is taken over by Sutekh, who manifests through her to create a skull-faced “Angel of Death”, at the same time as Harriet Arbringer suffers the same fate at UNIT HQ. Together, they release the “Dust of Death” across the universe and wipe out all life forms barring Sutekh himself, the Harbringers, the Doctor, Ruby Sunday and Mel Bush (who survived by escaping in the Remembered TARDIS). 

After the Doctor and Ruby Sunday defeated Sutekh, Susan returned to her former pleasant self, and was offered a job at UNIT by Kate Lethbridge-Stewart.