Bonn

Bonn is one of the Ten Pirates of Hawkins, and has one piece of the Treasure Map of Hawkins, which is needed in 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.

Easter Egg
This is in reference to one of the original game producers at Electronic Arts: Stewart Bonn.