There exist few humans in this world with the ability to manipulate their souls to form powerful weapons. Dubbed "Blazers," these people study and train at the prestigious Hagun Academy to become Mage-Knights; among the students is so-called failure Ikki Kurogane, the sole F-rated Blazer. However, when the worst student in the academy sees Stella Vermillion, an A-ranked Blazer who also happens to be a princess, naked, she challenges him to a duel with dire stakes—the loser becomes the slave of the winner. There's no possible way that Stella can lose, right? As he tries to prove his strength to a world that believes him to be the weakest, Ikki gains new friends, wisdom, and experience.

High school student Kaname Sudou receives an invitation from a classmate to play Darwin's Game, a mobile game he has never heard of. However, as soon as he opens the application, a green snake suddenly pops out from his phone screen and bites his neck, leaving him unconscious. Waking up in the infirmary without any signs of a snake bite, he is told by the school to take the rest of the day off. Although he is puzzled by what has happened, he dismisses the surreal experience as a hallucination and boards the train home. Unfortunately, his curiosity gets the better of him and he uses the application once again. As the application appears to be just like any other battle game, Kaname breathes out a sigh of relief and decides to start his first match. However, the pleasant surprise is short-lived, as his in-game opponent unexpectedly appears right in front of him and attempts to hunt him down with a knife. As he desperately runs for his life, Kaname puts two and two together and realizes that Darwin's Game is not an ordinary game, but rather, it's a brutal fight for survival.

Long ago, magic was abundant and enriched the lives of all people until its usage in war. To end the chaos, seven of the most powerful mages gave up their lives in order to seal all magic. Now, almost one thousand years later, their magic seal Magiaconatus hosts Granbelm, a monthly series of battles meant to determine who among its participants is worthy of the title of Princeps, the one true mage. On the night of a full moon, high school student Mangetsu Kohinata is suddenly transported to an illusionary world where six mages are participating in Granbelm. Mistaken for an enemy mage, Mangetsu is attacked by two mages until she is rescued by Shingetsu Ernesta Fukami and her Armanox Viola Katze. However, when Shingetsu is ambushed for protecting her, Magiaconatus grants Mangetsu the Armanox White Lily, allowing her to fight off Shingetsu's assailant. Overwhelmed by the revelations presented to her, Mangetsu decides to help her new friend fight in Granbelm and make her wish come true.

As a trainee of Santa Company, Noel White prepares for her test to become an official Tonttu, her assignment being "To find the most important thing for a Santa Claus." The deadline nears with an answer yet to be found, when a single letter from a child arrives late at the company. As the letter is about to be handled as a defect, Noel and friends set out on an adventure for the present - but will Noel find the answer to her assignment? Set a year after the events of the novel.