Lila Kreeg had an unhappy childhood. Her father hothoused her, forcing her to learn algebra at a young age and rapping her knuckles when she was wrong, whilst her mother often threatened her with Daleks and once told her that she hated her. Her parents were arguing about her one night when she decided to leave home.
After graduating, Lila's girlfriend, Helen, broke up with her. She embarked on research at the University of Cambridge, experimenting with teleportation using particle recombination technology in a project named Leapfrog. The project resulted in the death of a student volunteer, who was turned inside out. Wracked with guilt, she had a breakdown before coming to believe that the death had been destined and that she had no reason to feel guilty.
Lila was kicked out of Cambridge and faced a prison sentence, but she was saved by Magnus Drake, who kept her from being imprisoned and gave her a job at Drake Interplanetary to work on Project Yellow Brick. Because of Leapfrog, particle recombination technology was made illegal. (AUDIO: Faustian)
Project Yellow Brick
By 2223, a few years after Leapfrog, Lila was Director of R&E at Drake Interplanetary and was working with Eddi Bhole. During a failed test run, she accidentally caused temporal distortion, making contact with the Master and showing her visions of her past and one of Cathrin Travers' corpse. She launched a second test run to replicate the distortion despite being ordered not to by Drake and sees the Master, who promises to give her his knowledge should she free him.
Cathrin fired Lila, having security escort her off of the premises. She planned to continue the project and to sell the completed product to China, stealing the equipment with Eddi's help and promising Cathrin a 70% stake after Eddi sold her out to her. She successfully freed the Master, who killed Eddi, and promised him access to Drake Interplanetary in return for power and glory. They then went to the company premises, where the Master killed Drake and Cathrin. Whilst Lila did not want to watch Drake's death, she chose to watch Cathrin's. (AUDIO: Faustian)
For several months, Lila assisted the Master as his leading scientist, although she did not know what the Master was doing with all of the promethium that the Zhongguo Alliance was providing him with. She fled Ludgate Citadel with him after Vienna Salvatori's first assassination attempt and crashed in Notting Hill where they were taken captive by Sassparilla and taken to King Muggy, whom the Master told to kill Lila when he said that he did not wish to look weak by setting them both free.
After narrowly escaping death thanks to the arrival of Vienna and Artie, Lila, who was sceptical of the Master's claims to have been buying time and that he would not have let King Muggy kill her, fled with the Master to a tube station where she contacted Cutlass Leader. They both survived the Trogs and Lila left to meet the Zhongguo Alliance. (AUDIO: Prey)
The Dalek invasion
Lila's shuttle was redirected as a spacecraft approached Earth (AUDIO: Prey) and she was instead taken to the Vauxhall Building, where she had to convince the Master that she had not been the one to hire Vienna after he drew his gun on her. She detected the sixty Daleks which surrounded the building and prepared to defend herself and the Master from them, locking Vienna in a storeroom for a time per the Master's orders. Later, she listened to Vienna talk to the Dalek Litigator and offered to maintain her silence and to assist her in return for 20% of her fee; Vienna agreed to 15%.
Lila, in charge of the drones, partook in the massacre of the Daleks outside of the building, after which Vienna told her and the Master about Drake's clones. When the Master left to confront the Dalek Supreme, Lila and Vienna planned to capture him and went to Drake's bunker to gather technology for them to use, coming across Drake's improved Yellow Brick. After a Dalek attack, she and Vienna transported the equipment to the Dalek saucer at Trafalgar Plaza.
Lila boarded the Dalek saucer and found the Master, who told her that he would be leaving Earth in the ship and would devastate the planet so that nobody could see his failure. She refused the offer before being told that the only alternative was death, after which she told Vienna to activate Yellow Brick. The saucer and Daleks were pulled into the Time Vortex and, with a push from Lila, so was the Master. (AUDIO: Vengeance)
After the Master
In the Master's absence, Lila gained complete control of Drake Interplanetary and was offered a buyout by Raxle, one which she did not intend to accept due to the amount of potential good she could do in the position. She was visited by Vienna, whom she gave a collection of Dalek scraps and the offer of a short-range shuttle to take her to her ship still orbiting Earth. (AUDIO: Vengeance)
Lila was a genius with a stubborn streak "a mile wide" and little regard for authority when it got in the way of her achieving her goals. She had a strong mind which allowed her to resist the Master's influence, (AUDIO: Faustian) but she was deluded for some time that she was the one using the Master and not the other way around. (AUDIO: Vengeance)
Cathrin Travers (AUDIO: Faustian) and Li Zhao considered her to be one of the most gifted scientists on the planet. (AUDIO: Prey) Drake also knew her to be incredibly intelligent (AUDIO: Faustian) and to be one of his greatest hires, (AUDIO: Vengeance) although he did not believe that she was indispensable. (AUDIO: Faustian)
Behind the scenes
In writing Faustian, Robert Valentine wrote Lila as a three-dimensional protagonist to serve the same role that Rose Tyler served in Rose and The Christmas Invasion; that is, introducing the titular character. (BFX: Faustian)