There are two endings for the player to choose upon defeating King Allant.
Good Ending
This ending is chosen by leaving the Maiden in Black after her speech. The player character has resisted the temptation of the unfathomable power offered by the Old One, and in doing so, has saved Boletaria and the rest of the world by aiding the Maiden in Black in lulling the Old One back to slumber. The Old One and the Maiden vanish with the receding fog, and while Boletaria is safe, knowledge of the Soul Arts will once again be lost. The souls lost in the havoc wreaked by the demons will be forever lost, but the world now has a new monumental of unprecedented power to guard over it; the Slayer of Demons.
Evil Ending
This ending is chosen by slaying the Maiden in Black. The player character has succumbed to the temptation of power and will condemn the world itself in order to satisfy their appetite for souls. Sensing a new and powerful demon by its side, the Old One would soon engulf the entire world in the Deep Fog.