Meta-World

The Meta-World (メタ世界) is a secondary dimension in, separate from physical reality.

Purgatorio
Purgatorio is seen as the witch's realm and is where the "games" of Umineko no Naku Koro ni take place.

Most of the debating between Battler Ushiromiya and Beatrice take place in the Witch's Smoking Room, an otherworldly room within Purgatorio.

Sea of Fragments
The Sea of Fragments (カケラの海) is a vast, ocean-like space containing countless Fragments, prisms representing different universes. The sea appears in both and.

Time Void
The Meta-World seemingly appears in, specifically in , as the Time Void. In the opening scene of Minagoroshi-hen, Rika Furude is seen examining several different fragments before finally entering one. This location reappears in the second episode of as well as the first episode of  as the aforementioned Sea of Fragments.

Trivia

 * In Ougon Musou Kyoku, either team may attempt to enter the Meta-World for significant advantages and powerful moves.