Mokpo

Mokpo is a man living on Anodunos, who has gone totally mad, and flees from the bitter reality into a dream world, which he now thinks of as reality.

The Avatar met him in Ultima Underworld II inside the ice caves, but it became clear very fast that in order to flee from reality, he had become totally mad, thinking reality is a bad dream. But his seemingly insane ramblings about his "real" world interested the Avatar, so after finding the Dream Herb, he/she gave it Mokpo. When Mokpo was high on the plants, he gave interesting clues, speaking while sleeping.

Later, after traveling into the Ethereal Void, the Avatar met him again, but this time he was in his fantasy world of being "Mokpo the Great", thinking of himself as a mighty warrior, still saying that reality is false. The Avatar left him to his delusions after getting some more hints about the nature of this world and how to beat it.

Trivia

 * The ramblings of a stoned Mokpo, combined with what he says in the dream world, actually are the complete solution for all the puzzles in that dimension.
 * Many players had no idea that his ramblings were real, vital clues. One quite mean trap by the programmers.
 * Mokpo can be released from his delusions and becomes aware of his true surroundings.