Rumis, a deity in the Crystania pantheon, remained neutral during the war between the gods of light and darkness. When the Dragon Lords turned their aggression towards neutral deities, Rumis fled south alongside fellow neutrals, ultimately reaching the land of Crystania. There, Rumis ascended to become one of Crystania's five animal god kings.

This deity holds dominion over the Gods' Wall, an immense cliff formation acting as a physical and metaphysical barrier separating Crystania from the outside world. As guardian of this boundary, Rumis typically manifests by concealing its divine essence within the body of a snake, reflecting its serpentine association.