Elena

Princess Elena was the daughter of Lord Godwyn and his wife. Her mother died in childbirth, and soon after she was possessed by a sidhe. Her nurse, Grunhilda, was the pixie servant of the sidhe elder, and every night Grunhilda sprinkled Elena with pixie dust to calm her.

20 Years Later
Elena grew up as a clumsy (due to her changeling status), tomboyish girl, who enjoyed horseback riding. Sometime after her twentieth birthday, she made the journey to Camelot for her arranged marriage to Arthur Pendragon. Though they bonded over a horse ride through the forest, neither of them had any feelings for the other. Arthur in particular found her clumsy nature slightly irritating and unattractive. Eventually Merlin found out that Elena was a changeling, and part of a plot to put a sidhe on the throne of Camelot. The sidhe possessing her would take her over completely upon her marriage to Arthur. However, Merlin and Gaius managed to create a potion to force the sidhe out of her, and while Merlin held off and eventually killed Grunhilda, Gaius got Elena to drink the potion. The sidhe was then killed by Merlin. During her wedding, she and Arthur confessed that they were only marrying for duty, and neither had feelings for the other. Arthur later said he noticed something different about her as she came down the castle steps without falling. The last thing she said to Arthur was that if she wanted to be beaten in a horse race, he knew where she was.