The Doctor is a millennia-old alien being hailing from a far-off planet in the known universe known as Gallifrey. Natives to this planet branch into one of two categories: a standard, humanoid version, or a much more powerful version called a Time Lord, known for their mastery over time travel technology and who patrol all of time and space to maintain a sense of order and balance. The Doctor is one such Time Lord, except they eventually got fed up with the typical Time Lord bureaucracy left Gallifrey as a runaway. Craving adventure, they began fighting evil and injustice throughout the universe, traveling throughout space and time via the TARDIS. And thanks to the Doctor's unique method of healing, they have lived as several different incarnations, each one with the memories and experiences of the last. Across their various adventures, the Doctor has picked up several companions, mostly from planet Earth, and has been inspired countless times to save the lives of the innocent, no matter the cost.