The Sage decided to have a quiet life after death

The story is about a boy called Mizuno Hiroto got summoned to another world. Though after he died, he was able to travel back to earth and start a new life...... ---------------------- This is my first book, so I'm gonna state something. First, it's not gonna be perfect. Second, it's an sudden idea so don't expect much . Third, English is not my first language so don't expect fine Grammer. ---------------------- Also if I have some mistake, please point it out