The Gllia Region (analogue to the real-world Gaul region) is a land area located near the center of the Eresian continent, east of the Ispani peninsula and south of Britai. It contains the locations of Promalock, Esteria, Baldeux, and the titular Ys.
At first, the Gllia kingdom worships Norse god Grimnir as their patron god. Grimnir even bestowed them a gift: Grimwald Nox. In the Grimwald Nox, Grimnir command his demigods to fight the monsters that are created from the negative emotions of Gllian people, thus keeping the area peaceful.
However, after the Hundred Years' War, Grimnir fell along with Britai patron god Luki. After that, the Norse belief in the region starts to dwindle and eventually fade away, being replaced by Hieroglyph Church. The Norse believers are been persecuted by the Hieroglyph believers, and they had to retreat to the Deep Crypts -Evan Macha- for religious actions. Ironically, the crypt was built to prevent persecution from the Britai Luki worshipers, but end up used to hide from local Hieroglyph believers.