The year is 2222. It has been years since Tears of the New Moon, a mysterious rain, poured and wiped out almost the entire human race. The poisonous rain gave birth to deformed creatures devouring humans, and humanity fled from the danger. As means for survival, the humans then build an underground haven; Amasia. In this newly built dystopian city, in a pursuit of maintaining their existence, they run into an Artificial Intelligence named Magus. Not knowing how things will work between them, the story of how Humans and AI coinciding and trying to find their truths begin.

In a world where the Demon King has died, a host of demigods capable of felling him have inherited the world. A master fencer who can figure out how to take out their opponents with a single glance; a lancer so swift they can break the sound barrier; a wyvern rogue who fights with three legendary weapons at once; an all-powerful wizard who can speak thoughts into being; an angelic assassin who deals instant death. Eager to attain the title of "True Hero," these champions each pursue challenges against formidable foes and spark conflicts among themselves. The battle to determine the mightiest of the mighty begins.

The beginning of Light Magic and the Hero, an otome RPG, unfolds fairly normally: the heroine, Alicia Ehnleit, meets her three love interests one after another and then inevitably comes face-to-face with the villainess. Yumiella Dolkness may be of noble descent, but her dark hair and rare dark-type magic—both associated with the Demon Lord—spark fear in anyone who sees her. When she is five years old, Yumiella regains memories of her previous life in modern Japan, also realizing that her fate is to become the hidden boss that appears after Alicia and her suitors defeat the Demon Lord. Yumiella refuses to live as the game dictates and, as she prefers the game's fantasy elements over its romance, she decides to cultivate her magical skills and level up in secret. However, everything falls apart on the day of the Royal Academy's entrance ceremony. Yumiella's powers are measured at level 99—something thought impossible even for the royal knights, let alone a 15-year-old girl. With the royal family requesting her help, and everyone else insisting that she prove her strength, Yumiella realizes that her dream of a quiet life is no longer an option.

A young girl named Miru and Ran, a boy who appeared before Miru, embark on an adventure in an alternate world — but something tragic awaits them there...