Subternia is the Eternian underworld, a magical afterlife accessible through descent. The 2021 Masters of the Universe: Revelation made Subternia a major location in the show’s first part, with Teela’s band descending in pursuit of Adam’s spirit and Skeletor making a parallel descent for his own purposes. The space is rendered with biomechanical, bone-dominated imagery — one of the most visually distinctive locations in any MOTU continuity.
Catalogue source: heman.fandom.com (CC BY-SA 3.0).