Madou Monogatari

The plot begins with Ragnus being cursed by Yoggus, and getting sent to Arle's world. Mysterious creatures known as Yogs soon begin to appear throughout the world, along with their influence spreading onto others. With the help of Rulue, Carbuncle, and various party members recruited throughout the game, Arle resorts to defeating the Yogs, and eventually Yoggus itself.

The final game in the Madou Monogatari series, featuring the classic characters most players are probably more familiar with from the "Puyo Puyo" series and featuring the Lovecraftian deity Yog Sothoth as the primary antagonist.