As the Monster Age arrived and special abilities awakened, what awaited humanity was the end of the world. At the brink of the apocalypse, Frank Channing was sent back in time to the second year of the Monster Age. There, he awakened the Infinite Devouring System, allowing him to gain growth points by hunting the monsters. Along with it came a mysterious serpent-shaped mark on his arm. It could transform him into a powerful serpentine creature capable of wielding the very forces of the monster—seemingly tied to the secrets of the Blood Moon. From the system, Frank learned that he carried the mission of saving the world.
