Silbern

Silbern is where the Sternritter and their Soldat subordinates live alongside their emperor Yhwach. A frozen city roughly the size of the Seireitei sprawls around it, filled with seemingly deserted, similarly iced-over buildings. The name carries the German sense of silver and a Japanese reading meaning silver-wrought castle, which the Viz release renders as the Silver Cross Fortress.

The stronghold is a broad, two-level structure whose lower floor rests on six massive columns while the narrower upper floor sits atop a row of pillars pierced by slit windows. A stairway climbs to the base, an angular barrier with octagonal joints rings the whole site, and a pair of curving, tusk-like spires arch toward one another out front. Behind it looms a tall, cross-marked tower that Yhwach later uses as a launch point into the Soul King Palace. Ice sheathes every surface, bristling with stalagmites. The interior varies enormously, from cavernous assembly halls and a torch-lit throne room to the private quarters of individual Sternritter and the silver-tabled meeting room called Wörtlich Hall. Tier Harribel is held captive in a separate chamber suspended in midair, and ornate plates known as Gates of the Sun let occupants jump across the palace using the matching Keys of the Sun.

Silbern and its surrounding city occupy the Schatten Bereich, a shadow realm the Quincy wove from Reishi inside the Seireitei after their defeat a millennium earlier. That hiding place, invisible and undetectable to the Shinigami, is the reason the Wandenreich styled itself the invisible empire, though Yhwach can never remain outside it for long. During the second offensive he displaced the Seireitei outright with Silbern and its city to sidestep the time limit that had ended the earlier war. After he consumed the Soul King, Yhwach hauled the entire complex up to the Soul King Palace, reshaped it into a citadel he named Wahrwelt, and lined its halls with stone guardians. The palace met its end during Ichigo Kurosaki's final duel with Yhwach, when the sheer force of Ichigo's Merged Hollow Form tore most of it apart.