Adeola Oshodi

Adeola Oshodi, known familiarly as "Adi", was a technician at Torchwood One in Canary Wharf, where she worked on its free energy project. She died as the result of Cyberman infiltration of Torchwood Tower which preceeded the Battle of Canary Wharf in 2007. (TV: Army of Ghosts) She was a cousin of Martha Jones, with whom she shared a resemblence. (PROSE: Made of Steel, TV: Smith and Jones)

Death
She was finding a place to make a romantic liaison with a co-worker named Gareth Evans when she was seized and cyber-converted by Cybermen who had slipped through the Void through a breach in space-time. Her "upgrade" was internal, through an EarPod-like earpiece (or earpieces) linked with cyber-filament directly to her brain. She was killed definitively when her "earpieces" were overloaded by a signal from the Tenth Doctor. (TV: Army of Ghosts)

Legacy
When the Royal Hope Hospital she worked was relocated to the Moon in 2008, Martha recalled to the Tenth Doctor, among the alien appearances of recent years, "those Cybermen things." She noted that her cousin worked at Canary Wharf and never came home. The Doctor gave her his condolences and noted that he was present at the battle. (TV: Smith and Jones)

Martha recalled Adeola again when faced with the return of the Cybermen. Remembering that the Doctor was present at the Battle of Canary Wharf, she asked him if he had seen her, noting that she looked "a bit" like her. Internally, the Doctor recalled the memory of when he was forced to terminate Adeola, but avoid answering the question, saying that things got "pretty chaotic" and that a lot of people died before apologising again. (PROSE: Made of Steel)

Behind the scenes

 * Actress Freema Agyeman played the parts of both Adeola and Martha. The confirmation that the two characters were related first became public in the Made of Steel novella. It was actually released before the broadcast of Smith and Jones. (Made of Steel takes place after Smith and Jones and introduces the character.)
 * Russell T Davies stated in an interview that had he known Freema Agyeman would be such a good choice of actress for the upcoming new companion he would have rewritten Army of Ghosts so that Adeola survived.
 * Other examples of an actor guest-starring in the series in one role, only to return later as a recurring character in another role include Peter Purves, Nicholas Courtney, Ian Marter, Lalla Ward, Colin Baker, Eve Myles, Peter Capaldi and Karen Gillan.