Gestosu holds two large Shou ruins that were once great cities. In the last two centuries of the Horgon Era, these city-states fell to the Dead Ancestors and raids by the tyrant Tiya'lith; the same that would go on to establish the Tiya'lith Empire. By the start of the First Epoch, the Shou of Gestosu were gone from the valley, pushed south into Kalaran. Gestosu was a wasteland of death and decay where not even the Tiya'lith have interest in claiming it as territory.
In the Horgon Era, Demacian shamans used magic to entwine the essence of Shou spirits into their armor. This practice of spoiling spirits and tying them down, instead of letting them wander free, was an affront to the Shou. It gave rise to an great enmity between the two peoples that has never ended. It also led to the defilement of Gestosu and the creation of powerful undead whenever someone wearing Gestosu Chain died. Some of the undead that have risen from the bleak plains of Gestosu become Dead Ancestors. These powerful undead lords are in a never-ending war with the peoples of Shounejo and Tiya'lith.