Location from Genshin Impact by HoYoverse
A subterranean nation beneath Watatsumi Island, once called Byakuyakoku, where an ancient civilization lived in eternal darkness illuminated by an artificial sun.
Enkanomiya was originally a surface nation that sank beneath the ocean during a catastrophe predating the Archon War. Its people, cut off from the sun, constructed the Dainichi Mikoshi to survive in perpetual underground twilight. The civilization developed independently from surface Teyvat, preserving knowledge that Celestia actively suppressed above — including truths about the world's origins, the nature of the Archons, and humanity's relationship with the divine. The text 'Before Sun and Moon' found here contradicts Celestia's official history. Eventually the people of Enkanomiya were led to the surface by the serpent god Orobashi, becoming the ancestors of Watatsumi Island's inhabitants.
A vast underground cavern system housing the ruins of a Greco-Roman-inspired civilization. White marble columns and temple facades rise from dark waters, illuminated by Dainichi Mikoshi — a massive artificial sun constructed to replace the sky the people lost. Coral formations and deep-sea flora encroach on crumbling plazas, and the boundary between air and water blurs in the lowest chambers.
Also known as: Byakuyakoku, the Depths, the Sunken Nation