Extra Existence

Thirteen years ago, an unidentified object materialized in the heart of Shinjuku, forever altering the course of human history. This mysterious anomaly did not simply remain dormant; it began to periodically spawn terrifying demonic creatures that relentlessly assault the world. With each passing cycle of their emergence, these monstrous entities have steadily consumed civilization, pushing humanity to the very brink of extinction as the earth is slowly devoured. In a desperate bid for survival, the military embarked on a frantic search for a means to combat the unending tide of demons. Their efforts ultimately led to the discovery of a specialized weapon unlike any conventional armament. Known as "exex," this extraordinary power is not wielded externally but instead integrates directly into the human body itself. By fusing with individuals, exex transforms them into living weapons capable of standing against the demonic threat. As the world continues to be eaten away, those who bear this unique power represent humanity's final line of defense in a war where failure means total annihilation.