Mystery: the Substitute and the Form from Another World

The young baron unexpectedly acquired memories from an unrecorded past, and the extraordinary power he gained became a powerful stand-in ability. "Ha, this is definitely my era!" Jon Joestar, who learned about the historical process, was about to show off his talents and take the long steps to become a god, but the world underwent strange and unknown changes. Amazing magic, immortal knights, weird demons... Different worlds collide with each other and different rules are entangled with each other. This is a wonderful story with a mysterious world as the stage background. (You don't necessarily need to have read the original work to read the fanfics of Lord of Mysteries, JoJo's Bizarre Adventure, Harry Potter, Dark Souls, Chainsaw Man and other works, but it is recommended to read the original work first to get the best reading experience.)