Elizabeth X
I'm the bloody Queen, mate. Basically, I rule!
Elizabeth the Tenth, (also known as Liz 10) was the Queen of Britain when Earth was devastated by solar flares. She'd grown up on stories of the Doctor, as had her whole family.
She found a Star Whale and enslaved it (or so she thought she had; in actuality it volunteered) to form the base of Starship UK. She then wiped her mind so that she would not have to deal with the consequences. Her government slowed down her body clock, keeping her effectively immortal. She thought she was 50 and had been on the throne for ten years, not knowing she always lived the same ten years, always found out the truth about Starship UK at the end of it, and always wiped her mind once more. She also placed this system throughout the ship and everyone would always choose to forget. Those who didn't were mostly children and sent to the Star Whale but were not eaten. She feared that if the Star Whale was freed then it would fly off and kill all who lived on the ship. She wore a mask to disguise herself from the public whilst investigating.
300 years later, when The Doctor and Amy Pond came to Starship UK, they found out the truth and told Elizabeth. Amy freed the Star Whale but the beast continued to carry Starship UK as it was old, kind and the last of it's species, just like the Doctor. Liz then was able to live a happy life along with her kingdom. (DW: The Beast Below)
