Skulls & Bones
Susandra is a High-Cleric of Zon-Kuthon who is sired from a combination of Devil and Medusa. She has displayed powers of both lineages and has proven to be a powerful cleric as well.
She created an elaborate tomb for the Alden Family, worshippers of Zon-Kuthon millennia ago. However, the Alden family betrayed her and imprisoned her within the tomb, only to be released if she was able to sacrifice a good person to Zon-Kuthon.
When Zon-Kuthon was relegated to the Shadow Plane, he used his last power to create a time-stopped demi-plane to house the tomb, thus protecting his cleric from the ravages of time, as well as the sword which is a key to his power.
Sadly, the Shadow Warriors bravely, if not naively, entered the tombs and activated the sword and freed Susandra.