Water Labyrinth, also called Water Vein in other versions of Soulcalibur, is Yoshimitsu's home stage in Soulcalibur.

Japan is a land blessed with greenery, water, and giant labyrinth-like underground rivers, fed by water from the surface. These rivers lead to various points throughout the country.

The water that eventually reaches the underground river, after traveling through the earth for many years, is extremely cold and clear. The cavernous walls where the rivers travel through are covered with luminescent moss that provides the only source of light. The soft, pale blue light that emanates from the moss creates a dreamlike atmosphere.

Newly empowered by the Evil Seed, the vile ghost Gel-o-Fury shattered the seals in the bamboo forest and made its way into this vein. Taki challenged the ghost several times in this complex cave. Toki's assassins, while chasing Taki, could not resist Gel-o-Fury's aura and were absorbed into the great ghost. As Gel-o-Fury grew in power, Taki became convinced that the ghost was planning to exit the vein in Kyoto within the Buddha Hall of the Hoko Temple. She went ahead and planned to ambush the ghost in the hall.