Bonn, from Ultima VI
Bonn had shipwrecked on Dagger Isle, not far from the Shrine of Honesty, only a short time after killing Hawkins. The years in total isolation on the island had caused him to become totally insane. When the Avatar found him, he was only babbling total gibberish (he thought his name was the path of evil), but mentioned his basement, his "future grave". Down there, the map was found.
This is in reference to one of the original game producers at Electronic Arts: Stewart Bonn.