Saito was reincarnated to the other world at the age of 15, becomes the Great Sage, and defeated the Demon Lord. Shortly after that, the door connecting the other world and the real world opens, and S...more

Saito was reincarnated to the other world at the age of 15, becomes the Great Sage, and defeated the Demon Lord. Shortly after that, the door connecting the other world and the real world opens, and Saitou return to Japan with the power of the Great Sage.