Cass Fermazzi

Cass Fermazzi was a companion of the Eighth Doctor.

Cass travelled with the Doctor and Alex Campbell. She died when her ship crash-landed on the planet Karn, choosing death over being rescued by the Doctor, whom she did not recognise and whom she blamed for the death and destruction caused by the Time War.

Early life
Cass Fermazzi grew up in a "nothing town" (AUDIO: Vespertine) on one of the farm planets of the Gazrond Belt. (PROSE: The Day of the Doctor) She had enough brothers to man a flight deck (AUDIO: Meanwhile, Elsewhere) and only had her father to herself when he was telling her stories about Hudson Sage. When her father died, she sometimes chose to imagine that he was exploring like Sage did. (AUDIO: Vespertine)

As her family were poor, the only therapy that they could afford for Cass was a robot clown to take away some of her memories. However, the robot was already full of the Eleventh Doctor's memories and kept spewing them out, telling her to "never be cruel, never be cowardly" and giving her other advice that she considered cheesy. Nonetheless, the advice got to her. (PROSE: The Day of the Doctor)

Cass and her brothers once rescued a Mini 60 from the scrap shores. (AUDIO: Meanwhile, Elsewhere) According to one account, the Doctor would later learn that Cass had stowed away on a star freighter at the age of fourteen to see the wonders of the universe, but instead ended up running from the Last Great Time War. (PROSE: The Day of the Doctor)

Travels in the TARDIS
Cass saved up enough money to get a commission as an engineer on the EC-141, wanting to go out and see the universe. When the ship became destabilised by fractures in reality, she briefly found herself on Hervandel and met Alex Campbell, soon meeting the Eighth Doctor and a later version of Alex on the ship and working with them to save it. She helped thwart Hieronyme Friend, sabotaging her scoop to imprison the Garaban flies, and turned down a promotion from the Vice to join the Doctor and Alex in the TARDIS. (AUDIO: Meanwhile, Elsewhere)

For her first trip in the TARDIS, the Doctor took Cass to Station Twilight where they descended into the cavern below to examine the Vespertine, which was the ship of Cass's childhood hero, Hudson Sage. They found Hudson living inside a time lock, but he was killed after the temporal destabiliser that Rin Martolo had given them, claiming that it was a beacon, caused the time lock to decay and collapse. Cass believed that Rin had used them to kill Hudson, but learnt that she had only been targeting the ship and did not know that Hudson, her grandfather, was down there. (AUDIO: Vespertine)

Because of how much the Doctor spoke about them, Cass looked up the Daleks in the TARDIS information system and watched footage of them. She encountered them for the first time on an uninhabited planet where she and Alex distracted them whilst the Doctor went to sabotage a Battle TARDIS they had captured, but its explosion sent the three of them a year into the past and created a race of people who shared some of the trio's traits. Cass helped the city defend against the Dalek attack and disappeared after the Battle TARDIS was shut down, with the Doctor and Alex temporarily forgetting about her before promising to find her. (AUDIO: Previously, Next Time)

Fighting in the Time War
After helping an old soldier dying in a crater full of mud snakes, Cass realised that avoiding the Time War was impossible and decided to listen to the advice of the robot clown when she was young. She briefly met the Thirteenth Doctor, whom she believed to be a medtech and who handed her the soldier's bandolier.

Cass went on to crew a gunship for four years, during which she survived an encounter with the Nightmare Child, witnessed the massacre of Skull Moon and fought in the ruins of the Ulterium. One day, the ship fought off a Dalek fleet from the feeding hives of the Vantross and was attacked by a Time Lord battle cruiser, the crew of which were frustrated that Cass had got between them and the Daleks. (PROSE: The Day of the Doctor) As the only one who was not panicking, she teleported her colleagues off of the ship and onto the nearest planet. (TV: The Night of the Doctor)

Death
Upon realising that a safe crash-landing was impossible, (PROSE: The Day of the Doctor) Cass sent out a distress call which attracted the attention of the Eighth Doctor. He came aboard in his TARDIS and tried to rescue her, but she refused to join him upon learning that he was a Time Lord and deadlocked a door between them, telling him to return to his battlefield. The Doctor remained on the ship with her and the two of them died when the ship crashed onto Karn. (TV: The Night of the Doctor)

Post-mortem
Whilst the Sisterhood of Karn were able to revive the Doctor long enough for him to regenerate, Ohila claimed that Cass's injuries were too severe for the Elixir of Life to heal. Her death was the catalyst for the Doctor to regenerate into a warrior, who immediately claimed her bandolier as a reminder of what he would be fighting for. (TV: The Night of the Doctor)

According to one account, the Sisterhood gave Cass a funeral which the Doctor refused to attend, although he did visit her grave after the ceremony to apologise to her. (AUDIO: Light the Flame) According to another, the Doctor spent some time searching for Cass's family and eventually returned her body to them. (PROSE: The Day of the Doctor)

Other realities
A version of Cass who existed in the Daft Dimension seemingly suffered the same fate as her N-Space counterpart, for which the Eighth Doctor also apologised, before attempting to initiate his regeneration. (COMIC: The Daft Dimension 499)

Personality
to be added

Behind the scenes

 * Layla Bridge, Emma Campbell-Jones's character in The Keeper of Light, was implied to be Cass. However, this was not the case.
 * In response to a meme on Twitter, Big Finish joked that "Cass" was short for "Stu".