Shhh, It's Looking at You

When the NPC male protagonist in the scenic spot opened a book "Secret of Immortality", he accidentally traveled through time and became a scholar with the same name. That day he was invited to attend the wedding. Everyone was very happy that day, but he was the only one who saw the funeral—— As everyone knows, it is a world where demons and monsters are rampant (only a few people know it) And "it" naturally knows about his abnormality... After that, the book "Secret of Immortality" reappeared—— At this point, he has a new identity. And "it" opened their era.