Nobuaki Kanazawa is a high schooler. One day, he receives an email with an order from someone calling themselves "king". At first, the orders were normal. However, they started to escalate as time passed. Anyone not following the order was to be "punished" with "death"... The "King's Game" with their lives on the line has started!!! What awaits Nobuaki, who's facing against the invisible "king"!? (Source: Coolmic)

"The King's orders are absolute. Fail to obey, and you will be punished." 30 years ago in the remote Yonaki Village, a black envelope is delivered to a single villager. The command inside threatens to draw the entire population into a terrible tragedy! Take a deep breath, steady your heart, and prepare for a shocking, terrifying survival horror adventure! The latest chapter in the wildly popular "King's Game: Origin" saga has begun. It all starts here!

Side story of Ousama Game; takes place around the same time as Ousama Game: Shuukyoku. While Nobuaki Kanazawa and Natsuko Honda struggle to escape the curse of the King's game, far away, two schoolgirls in search of thrills break into an abandoned school at night. On the wall, in the notebooks, they find messages of hatred and anger... One of them particularly intrigues them: "Who is the King?" A year earlier, it was in this high school that Natsuko had her first experience of the cruel survival game! At that time, she only thought of one thing: to save her friends, and especially Kentaro, the boy she loved... But good intentions are no match for the King's cruelty... How far will Natsuko and Kentaro go to survive

The winner of the first edition of the King's Game is transferred to a new school. After being initially afraid to make new friends, traumatized by his experience in the past, he starts to forget the King's Game and sympathize with his new friends. That's when the new King's Game starts.

The students of Kamishiro High School class 2-A swore revenge on their homeroom teacher, Takao Nanami. Against her, a fake suicide had been concerted, meant to be played out by one of her students, whose actual death would later sink the class into confusion. Who soiled the water with blood? Skinned of its trust, their friendship became an urge to sate each other's hunger.

The "King" has given his order, and his word is law! Kanazawa Nobuaki and his 31 classmates all receive a command in the form of a text from the King; failure to carry out the order results in death. It's a battle, not against the king but against themselves. Whom can they trust? Who will do anything to live?