Naze Boku no Sekai wo Daremo Oboeteinai no ka?

In the past there si a time when the five superpower rivers faced each other and the winner would own the earth. Humanity takes over all of them and wins with the help of Hero Sid. Then suddenly a boy with the name Kai in front of him wrote the story. In the new rewritten form h, I knew that Humanity lost the fight and now demons rule over the world. He can’t do anything cause he is stuck in his written fate. With the help of a girl named Rinne, he ran from his fate and now he with the help of a sword challenged all the enemies and started to remove them.