The Underworld is a mysterious and dangerous realm featured in the action role-playing game Shadow Tower. It is the destination to which the Holy Land of Zeptar, including its central tower, has been mysteriously transported. The Underworld is characterized by its dark and foreboding atmosphere, inhabited by malevolent demons and other sinister entities. As the protagonist, Ruus Hardy, descends into the depths of the Underworld, players must navigate treacherous environments, engage in combat, and unravel the mysteries that lie within. The Underworld poses numerous challenges and serves as the primary setting for the game's quests and encounters.