"Listen up, my beloved descendants. Your founding ancestor has returned." The most powerful Demon King in history, Anos, known for his tyrannical rule 2000 years ago, has been reincarnated. Entrance exams are being held at the Demon King Academy where they train his descendants to be his successor and become Demon Lords. The entrance exam is a practical test where students must duel each other. Bored of the war-torn world of 2000 years ago, the tyrannical Demon King, Anos, appears on the scene.

Though he is the founding ancestor and possesses enormous magical powers, Anos is cast as a misfit at the Academy. Unperturbed by this unjust treatment, he continues to demonstrate his overwhelming powers and takes part in the team competition exam as a leader. His classmates mock him for being a hybrid, and the only teammate he can find is Misha. Their rival team is led by Sasha, Misha's older sister, who looks down on Misha and calls her a "junk doll."

"One last thing, I'm glad I got to meet you." Without being able to understand Sasha's true intent behind these final words, much time has passed, and Ivis, one of the Seven Elder Demon Emperors, holds a special class at the Demon King Academy called the Great Magic Training. The Seven Elder Demon Emperors are seven demons that Anos, the founding ancestor, created from his own blood. Emilia implores Anos to act respectfully to Ivis, but without hesitation, he speaks to Ivis in a condescending tone.

Misha confesses the shocking truth that, "At midnight on my 15th birthday, I'm going to disappear." Misha was never supposed to exist in this world in the first place, but due to Ivis Necron's magic, she was living a transient life. She had resigned to her fate that she will only live for 15 years, but Anos tells her, "There are two things that I do not understand. Regret and saying that something is impossible." The misfit crushes the tragedy and unjust fate that binds the two sisters.

Shortly after Anos' encounter with Misha and Sasha as well as his battle with Ivis, a transfer student named Ray enters the Demon Academy. As the Master of Magic Sword and powerful enough to defeat the Seven Elder Demon Emperors, Ray makes it clear that he wants to join a team with a capable leader, and requests to join Anos' team. However, Anos refuses and proposes to Ray that, "If you prove that you are worthy, I will allow you to become one of my followers." Ray decides to form his own team and battles head-to-head with Team Anos during the team competition exam.

In recognition of their accomplishments in the team competition exam, Anos welcomes Lay and Misa to his team. The team gathers at Anos' home to celebrate, but shortly after, Lay and Anos are announced as participants in the Magic Sword Tournament. Lay rejoices at the chance for a rematch with Anos, but Anos suspects that there is an ulterior motive. The situation escalates when Misa takes Anos to meet one of the Seven Elder Demon Emperors, Melheis Boran.