Iss'leek, from Ultima Underworld
When the Avatar met him in Ultima Underworld I, he, like the other Lizard Men, couldn't speak the common tongue. However, he had a scroll prepared by Murgo, in which he stated that he desired a red gem. Giving him one, he in return revealed the secret of the "Water Walk" spell.
Later, he went deeper underground, like all the Lizard Men, when the Abyss was destroyed.