Reiōkyū

The palace floating above the Soul Society where the Soul King rests, protected by the Royal Guard. Double-click to enter.

Reaching it is the goal of both of the series' great antagonists: Aizen wants to create the Ōken to open its gate, Yhwach actually invades it, exploiting the opening left by the Royal Guard's pillars. The palace then becomes Wahrwelt, the capital with which Yhwach means to merge the three worlds into one.