Never too powerful
After a failed teleportation experiment, Earth merges with another world, causing the appearance of demons who seek to destroy it. A war erupts between humans and these creatures. During the fusion, a mysterious energy wave strikes humanity, awakening power marks in some individuals, granting them immense strength. These chosen ones become known as Demon Slayers, or God Slayers, the only ones capable of fighting back.
Despite a fragile peace, demon attacks remain frequent, and only the Demon Slayers can stop them. Igris, a frail young man without a mark, has no interest in demons or war. But one day, as he returns from university, he witnesses his best friend being killed by a demon. Consumed by rage, he kills the creature and awakens his own mark.
From that moment on, he has only one goal: to prove the Demon Slayers are useless for failing to save his friend… and to eradicate every last demon.