Satoru Gojo had been the Emperor's dog his entire life, following all of his orders, e ven the most vile ones. But... one night, the Emperor, the one Satoru obeyed, killed him. Satoru died with the thought of taking revenge and killing the Emperor.

Suguru, the demon of vengeance, was resting in his castle at this time before his soul was bound to Satoru's soul to carry out his revenge. When Satoru opened his eyes, he realized that he was a boy of 16 years old again. He needed to go to the academy. The only thought on his mind was to kill the emperor. But he still had a lot to learn, he is no longer the strongest swordsman on the continent, but a teenager. But suddenly, a demon appeared in front of him. Satoru grabbed the sword, looking at the demon. (in the first seconds, he thought it was an angel because of its beauty)

— "...who are you?" — he said, raising an eyebrow