Powerful weapons and Armour found in Ultima III (My second favourite Ultima, after Ultima IV). Mystics were not as strong as some of the other weapons, but they were extremely light.

Spoiler! (but if you haven't played ultima 3 by now, you probably never will) Mystics were found by going to a small island to the north of sosaria, and using the (O)ther command and typing <dig>