Lacuna

Dark inter-bubble space resembling an egg carton of sunken bubbles in varying states of intact or popped. Features a red glowing horizon and constant icy winds. Acts as the exterior void between contained bubble worlds.

Lacuna begins as an enigmatic, egg-carton void of sunken bubbles and icy winds that separates the bubble worlds of the fourth floor. Across subsequent books it evolves from a mere interstitial space into a dynamic, multi-layered realm that characters must traverse, manipulate, and weaponize. Its red horizon and constant winds become both navigational hazards and tactical opportunities, while its bubble structure shifts from static containment to a fragile network that can be ruptured, traversed, or even collapsed for strategic advantage.