The Dome is an entity present in nearly every world imaginable. Its hallowed halls stretch on for unfathomable lengths, and contain a countless number of rooms and doors leading to a myriad of places, beautiful and grotesque, familiar and unknown, peaceful and hostile. It houses all of these conflicting places in one omnipresent, seemingly omniscient structure. Nothing appears to be beyond the grasp and capability of the Dome, which has brought fighters from across alternate universes to its doorsteps.
Each of these fighters perceives the great structure in a different way, one perhaps seeing a fairytale castle of old, others perhaps a sprawling scientific complex, but some things remain consistent with each visitor. The large, central "dome" shape part of the roof from which it derives its name, the Dome gardens and courtyards, the cafeterias, training rooms, and immense libraries all exist no matter who you ask.