Sutek

Sutek is a very powerful Mage, who seems to be chased by misfortune at every turn.

Sutek was on the same ship as Captain Johne when it was sucked into the Underworld, but was spared from being killed as his other companions were. Leaving Johne and finding a way back to the surface, Sutek built a house on Spektran and researched the Shadowlords. In Ultima V he had found out enough to tell the Avatar exactly how they could be destroyed.

Shortly after that, the pirates under Captain Hawkins chased him off-island. Moving to Blackthorn's empty castle, a magical accident caused him to go mad. In Ultima VI the Avatar saw the results of Sutek's experiments: killer bunnies and monstrous animals with two heads. Sutek wasn't hostile towards the Avatar, and revealed that the balloonist had travelled into the dungeon under the castle. The Avatar then left him alone to his madness.

Shortly later, righteous warriors stormed the castle to kill the mad mage. Sutek's spell against them misfired, turning him to stone. His statue was dumped into the sea and the castle torched. His further fate is unknown.

Trivia

 * Sutek also created the Pushme Pullyu, a two-headed horse full of riddles.
 * In Ultima VI, Terfin was actually named "Sutek's' Isle," which meant his presence there wasn't really a secret at all.
 * His name was probably taken from the ancient Egyptian deity (more commonly known as Set).