Monica Everett, the Silent Witch, is the only mage in the world who can use unchanted magecraft, a true hero who singlehandedly defeated a legendary black dragon. However, this young genius is actually...super-duper shy! That's right: She learned to cast spells silently just to avoid speaking in public, and despite her power, she has zero self-confidence. Now Monica has been tasked with secretly guarding the second prince. Can she keep it together as she faces both the evil forces targeting the prince and the terrors of social interaction?

Two years ago, the death of Naoto Watari's parents left him as the sole caretaker for his younger sister Suzushiro "Suzu" Watari and forced him to move in with their aunt. So devoted is he to Suzu that he refuses to join clubs or even hang out with anyone, earning him snide comments and the title of "siscon" at his new school. But as long as Suzu is safe and happy, Naoto doesn't care what everyone else says. However, his sneering classmates may turn out to be the least of his worries. The sudden transfer of a girl named Satsuki Tachibana brings back traumatic memories from his past—a past she had a hand in making so unpleasant. Nasty secrets, unknown to Naoto, begin to surface with her arrival, threatening his new life.

Individuals with Momotarou and Oni blood coursing through their veins maintain a longstanding rivalry. The Oni are careless, rash, and disorderly, while the Momotarou protect the human world from the uncontrollable Oni. Shiki Ichinose is a reckless and irresponsible teenager, aware of his defiance and even proud of his expulsion from school. Despite Shiki's rebellious attitude, his foster father, Tsuyoshi, cares about him deeply. Tsuyoshi's selfless love is soon shown in an explosive incident when a Momotarou barges in looking for Shiki. As a Momotarou himself, Tsuyoshi has been hiding Shiki for years and keeping his Oni origins a secret even from him. As he gives up his life to save Shiki and confesses everything in his dying breath, Shiki's Oni blood awakens for the first time, transforming him into an unruly monster overflowing with rage and a thirst for revenge. Shiki's momentary outburst attracts the attention of Naito Mudano, an Oni teacher at the Rakshasa Academy—an institution for young Oni in need of understanding and perfecting their powers. Before Shiki can avenge his father, he must learn to control his headstrong and impulsive nature and, above all, fight against his own demonic blood.

"She" was supposed to be a beacon of hope. But now her anger and hatred have turned into flames of war and are about to engulf the people. Only Rhodes Island, a neutral organization, can stop Reunion's rampage and the conspiracy behind it. Amiya and the others head towards Chernobog's Core City, which is on a collision course with Lungmen. What fate awaits them there...