Kallistan

Kallistan is a Mountain Man who'd been taken prisoner by Tyball and who has an important item.

When the Avatar freed him from his cell in Ultima Underworld I on the severth level of the Abyss, Kallistan was mistrustful, until the Avatar proved to know Goldthirst by giving his password "Deco Morono".

Kallistan gave the Avatar the Crystal Splinter, explaining that he'd found it during his forced mining labor and that it could open the secret tombs to create shortcuts through the level, but warned that the tomb had been defiled by evil and that also the hero should't disurb the peace of the dead burried there.