Greyson, from Ultima V: Lazarus
Speaking with him during the day on the town square, Greyson said that he was an adventurer who had been many places and seen many things. He had seen the Stone Guardians, and knew how to gain access to the Codex of Ultimate Wisdom.
After a while, Greyson asked the Avatar who the true king was. The Avatar didn't hesitate a moment to declare that it was Lord British. This was much to Greyson's pleasure, since he didn't accept Blackthorn's dictatorship, and thus revealed the mantra of Compassion to the Avatar.