Cornelius Sigan

"He could change day into night, turn the tides, and legend has it, his spells helped build Camelot itself."

- Gaius on Sigan

Cornelius Sigan was the greatest sorcerer Camelot has ever known, before Merlin.

Early Life
It is said that when he was first alive he could turn the tides, change day into night and even helped build Camelot itself. His life's mission was to defeat death and he swore to one day return from the grave. Sigan became too powerful and the King at the time ordered him to be executed. Before his death, Sigan cursed Camelot, saying that he would one day return and raze the city to the ground. It was said that he didn't want his wealth and power to die with him and worked on a way to cheat death.

Return
This was revealed to be true hundreds of years later. After Camelot workers uncovered his tomb, a thief called Cedric worked his way up to a position in the Royal Household and used this to enter the tomb. He intended to steal Sigan's riches and jewels but found a large blue heartshaped jewel. The jewel contained Sigan's soul and he possessed Cedric, Sigan subsequently launching an attack on Camelot that forced Merlin to ask Kilgharrah for help.

After witnessing Merlin's magic, Sigan suggested that he and Merlin form an alliance, but when Merlin rejected the offer Sigan attempted to possess him. Using a spell that Kilgharrah had recently taught him, Merlin was able to trap Sigan's soul back in the jewel while it was in the air. Uther sealed up the vault where the tomb and soul of Cornelius Sigan lay (The Curse of Cornelius Sigan).

Abilities
Cornelius Sigan was described as the most powerful sorcerer ever to live, while he was alive, he was said, to be able control the tides, and even change night to day. His powers were so great that he was able to immortalise his own soul, and kept it alive after his death, by containing it in a jewel.

Upon gaining a new body, his powers remained intact, as he was able to possess another, and could animate every gargoyle in Camelot and control it.

He was only defeated by an ancient and powerful spell that the Great Dragon told Merlin, that trapped his soul back in the jewel.

Trivia

 * Cornelius shares similarities with the character of Lord Voldemort from the Harry Potter series by J.K. Rowling. But a major difference is that Cornelius Sigan has a nose, as well as hair and mustache. However, those were the characteristics of Cedric so the true appearance of Cornelius Sigan remains unknown.