Cass Fermazzi

Cass Fermazzi (PROSE: The Day of the Doctor) was the sole remaining pilot of a space gunship. She died when the ship crash-landed on the planet Karn, committing suicide by rejecting the aid of her rescuer. (TV: The Night of the Doctor)

History
Cass grew up on one of the farm planets of the Gazrond Belt, but at age fourteen she stowed away on a star freighter to see the universe. However, she became trapped in the Last Great Time War. A medtech gave her an old dead soldier's bandolier, and with it Cass tried to enter the fighting. She crewed a gunship for four years, surviving the Nightmare Child, seeing the massacre of Skull Moon, and fighting in the ruins of the Ulterium.

One day, Cass and her crew fought off a Dalek fleet from the feeding hives of the Vantross, but after departing they were attacked by a Time Lord battle cruiser that was frustrated they had gotten between it and the Daleks. As the only one who wasn't panicking, Cass teleported the rest of the crew off the ship onto the nearest planet before making a call for help, which was picked up by the Eighth Doctor. (PROSE: The Day of the Doctor) He materialised his the Doctor's TARDIS onboard and tried to rescue her, but, recognising him as a Time Lord, Cass chose death, professing that the Time Lords were no different from the Daleks. The Doctor refused to leave her side even when it meant he would also be killed in the crash.

Though Cass' body was recovered by the Sisterhood of Karn and they were able to revive the Doctor, her injuries were too severe for even their Elixir of Life to heal. Her death inspired the Doctor to finally take part in the war. He claimed her bandolier as a reminder of what he would be fighting for and chose to regenerate into a warrior. (TV: The Night of the Doctor, PROSE: The Day of the Doctor)