Sophia

"I was nearly killed. For a moment, I felt what it would be like to die a mortal death. He saved me. Someone so weak, so feeble, saved me! I can't bear to be like this a moment longer."

- Sophia on Arthur saving her.

Sophia was a young Sidhe who was exiled from Avalon, the land of eternal youth, when her father Aulfric killed another Sidhe. She was only allowed back into Avalon if she was to find the soul of a mortal prince for the Sidhe. Sophia and Aulfric began plotting that this soul would be from Arthur Pendragon.

Biography
Sophia and her father Aulfric are forced out of Avalon and given mortal bodies. However, they are allowed to maintain their magic powers. Aulfric wishes to allow Sophia access to return to Avalon and convinces her to enchant Arthur Pendragon so that they can sacrifice him to the Sidhe, who require the soul of a mortal prince. They set it up in the forest so that it seems like they are being attacked by Terence and his thugs. When Arthur and Merlin run to their aid, Arthur gets a good look at whom he rescues. He is immediately attracted to Sophia's beauty and she thanks him for saving her. The two sidhe pose as a noble family and Uther considered them guests in the castle of Camelot. Arthur grows more and more fond of Sophia, and they go out into the woods together many times, in one case being attacked by raiders, from whom Arthur saves Sophia again.

Soon however, the Sidhe realise that Merlin, Gaius, and Morgana are on to them, and they know they have to act quickly. Soon, Sophia has Arthur enchanted, and he listens to whatever she says because they are "in love". When Merlin tries to tell Arthur that the Sidhe are trying to kill him, Sophia notices Arthur's slight hesitation, as he starts to listen to Merlin, but soon her father blasts the servant with his magic staff, and they leave him unconscious, assuming he will die. Before the ceremony could begin, Aulfric reveals to Sophia that he will not be going with her as he is doomed to remain mortal for his crime. This caused Sophia to weep, before reluctantly starting the ritual.

Merlin turns up at the last minute and saves Arthur by killing both Aulfric and Sophia with Sophia's staff. Merlin keeps her staff afterwards (The Gates of Avalon).

Personality
Sophia was beautiful in her human form, but treacherous inside. She was selfish and sly; while she made the pretence of loving Arthur, she was contemptuous after he saved her life, furious that she had been lowered to a state where she needed to be saved by someone far less powerful than she had been. When Morgana told her that she knew what she was up to, and that she would not let her hurt Arthur, Sophia gave her a snooty glare and stated that jealousy was such an unattractive trait in a woman. However, Sophia revealed a soft spot for her father when she didn't want to leave him and return to Avalon alone, she sobbed and said that she would never forget him. Despite the fact that she took advantage of Arthur, it is possible that she was trying to save her own life, as it is mentioned by her father that the elders would take her soul if she did not take Arthur's.

Trivia

 * Sophia is greek for "Wisdom".