Nox The Ogre
Nox was trapped as a disembodied head in a jar that was cursed to never die until he gave an apology to the adventurers because he was the one that trapped them in a time field for over a millennium.
Our lost heroes exit from their long sleep inside of White Plume Mountain only to discover that they have been kept in stasis for over 2000 years and are being forced into a new world that has changed greatly from what they remember.