After losing his childhood friend to a popular boy Souji Karasuyama dies after being hit by a truck whilst floating in the abyss of death he hears a voice calling out to him and reaches out to the voice meeting a black knight in the process who gets absorbed, he finds himself in the castle of the Demon King. His goal was to defeat the Hero and his party all of whom are people he knew in his previous life. Now a new man he will live his life as a new being.