The mountain is highly significant to Calegia's history, as the ceremony celebrating the kingdom's founding was held here. The interior is similar to the architecture of the Sacred Beast shrines. During the events of the story, the group battles the Four Stars at the mouth of the mountain in a final showdown that ends in defeat for the King's Shield quartet. After the fight, the Four Stars are in disbelief at their loss. While the group manages to convince Walto and Militsa to abandon their cause, Tohma and Saleh remain hostile.
Ultimately, Walto and Militsa leave, while Saleh and Tohma kill each other. Deep within Mount Sovereign, Zilva Madigan appears a final time, berating the Four Stars for failing to stall the group. She tells them that she shall obtain the Sacred Beast King's power and save the world by eliminating all Huma and building a country solely for Gajuma, the "chosen people". After an intense battle, Zilva dies, leaving the group to communicate with the Sacred Beasts about the current situation.