Why Does Nobody Remember Me in This World? - S01

Humanity once waged a desperate war against four dominant races-angels, demons, undead, and humanoid beasts. Their only hope was the legendary champion Sid, who defeated the enemy champions and sealed their armies inside four pyramids. Centuries later, Sid’s deeds have faded into myth, and Kai Sakura Vento is one of many soldiers assigned to guard the pyramids, ensuring their ancient foes remain imprisoned. One ordinary day, while relaxing with his friend Jeanne E. Anise, the world is suddenly "overwritten." Kai is thrust into an alternate reality where demons have nearly wiped out humanity, forcing the survivors into hiding. Worse, no one remembers him-not even Jeanne, now leading a resistance against the demons. Searching for answers in the ruins of his old world, Kai meets Rinne, a mysterious girl trapped inside a pyramid. When he inherits Sid’s fabled sword, Codeholder, he frees her. Now, Kai, Rinne, and Jeanne must fight to liberate humanity. But to restore his original world, Kai must first unravel the mystery behind reality’s sudden and catastrophic shift.