Sir Arbuthnot

Sir Arbuthnot is the former royal coinmaker, who'd fled to the lighthouse of Greyhaven in Ultima V.

Some time prior to Ultima V, Shamino and Dupre secretly ordered him to make the Codex Coin in order to summon the Avatar back to Britannia. He did as told, but the regime got word of it and he was put on the wanted list, being forced to flee to Greyhaven for safety. Sir Arbuthnot then had a suspiction and asked the Avatar about the current regime. The Avatar replied being against it, and when Sir Arbuthnot further asked about the true Avatar, the hero revealed the truth to him. Sir Arbuthnot felt honored that his hard work had paid off in the end.

Ultima V: Lazarus
In the Ultima V: Lazarus version, his role was much expanded and he told a long and complicated story, after being shown the Codex Coin as proof of the Avatar's identity. Also he was involved in a supply chain to Serpent's Hold, which was under a blockade of the Oppression.