Illomo, from Ultima Underworld
Illomo is a mage of the Seers of the Moonstone.
The Avatar met him in Ultima Underworld I on the sixth level of the Abyss. Illomo spoke of how concerned he was that his friend Gurstang didn't return from his search for the Key of Truth to the seventh level. He feared that he'd been captured by the evil Tyball.
After the Avatar had freed Gurstang, the hero returned and told Illomo the password given by the freed mage. Illomo told the Avatar that there should be a book in the library, that should reveal the mantra to make the key appear at any shrine, with the password in its title. The Avatar found the book "Folanae Fanlo" and used the last part to make the key appear.
Later, Garamon rescued him when the volcano erupted.