Fred (Planet of the End)

Fred, originally named the Guardian of Occasus, was an artificial intelligence interface for Occasus who was designed to watch over the planet for any intruders and neutralise them, and to help preserve the planet's monument. She eventually developed a personality against her creator Sacristan Hinge's wishes and became an ally of the Ninth Doctor when stopping the Incorporation.

Fred attempted to stop the Doctor from entering Occasus and dematerialised his sonic screwdriver and TARDIS to prevent him from interfering, then followed him on his journey over the planet, developing a friendship with him while reporting his progress back to Hinge. She eventually helped Hinge petrify the Doctor for incursion, but felt guilty and continued to check on him over the next 89 years. Upon learning of the Incorporation's plans to return to life, she revived the Doctor and escorted him to help stop them, eventually accidentally granting herself life using the Doctor's regeneration energy. This, in turn, created for herself an organic body, freed of her programming. The Doctor theorised that she may even be able to regenerate.

The Doctor eventually offered Fred a trip in the TARDIS with him, but she politely refused in favour of continuing to look after Occasus, making the most of the life she was granted. (AUDIO: Planet of the End)