Trix MacMillan

Beatrix MacMillan, also known as Trix, was a companion of the Eighth Doctor. She was born Patricia Joanne Pullman.

Biography
Patricia Joanne Pullman was a con artist, who was wanted by the authorities for her murdering her father. (PROSE: The Gallifrey Chronicles) Pullman eventually adopted the name "Trix MacMillan".

She first met the Eighth Doctor when she had been hired by Sabbath to pose as a descendant of Tsar Nicholas II. After Sabbath had punched a hole in reality and the Doctor had to give chase, Trix asked if she could come along. The Doctor refused to let a con artist and a thief aboard the TARDIS, but she stowed away nevertheless, avoiding detection by the Doctor and his companions for a long time. (PROSE: Time Zero)

A shadowy figure later appeared and implied to Lyeene that Trix had stowed away on the TARDIS and avoided detection. (PROSE: The Last Resort)

When Trix was discovered, the Doctor did not punish her or make her leave the TARDIS, to Anji Kapoor's annoyance. Like many of the Doctor's other companions, Trix had a habit of wandering off, and had small adventures of her own before ending up back with the Doctor. (PROSE: Timeless)

On a visit to Espero, Trix was possessed by a Maker named Reo. (PROSE: Halflife)

Trix helped the Doctor to uncover the truth behind Old Man Crawley. While on Earth in that period she left behind copies of the Financial Times for Anji to collect. (PROSE: The Deadstone Memorial)

Trix later developed a relationship with Fitz Kreiner and planned to settle down with him after they had defeated the Vore with the Doctor. (PROSE: The Gallifrey Chronicles)

However, she and Fitz would continue to travel with the Doctor for a time. On one trip, they discovered a planet where temporally-anomalous Neanderthals were being herded as temporal weapons in preparation for a time war. (PROSE: We Can't Stop What's Coming)

Personality
Trix was a flawed and somewhat troubled companion of the Doctor, living under a false name and running from her past. (PROSE: The Gallifrey Chronicles) Trix was initially deceptive, being skilled in disguises, which proved to be very useful. This was due to her not wanting to feel conspicuous, an attitude that was further reflected by Trix being uncomfortable when dealing with physical injuries. (PROSE: Halflife) Trix could also be rather materialistic, such as an occasion where she stole a valuable locket rather contact the Doctor for help. (PROSE: Emotional Chemistry) However, Trix had great reserves of compassion, such as when she comforted temporary visitors to the Doctor's TARDIS, even while being in hiding, (PROSE: Reckless Engineering, The Last Resort) giving Guy Adams a winning lottery ticket after his manipulations by Kalicum. (PROSE: Timeless) Most notably, she befriended Prince Edward and Richard, the day before the supposed deaths in the Tower of London, and conforted them with a modified version of Cinderella. (PROSE: Sometime Never...)

Trix often disagreed with the Doctor. However, over time the Doctor helped her come to terms with herself and feel settled in her life. (PROSE: The Gallifrey Chronicles)

Behind the scenes
Trix was depicted in the DWM 341 preview of Halflife.