Edit: Found it, it's https://mangadex.org/title/630fcb7b-a262-4c92-b0c7-1323392f1b67/tada-no-murabito-no-boku-ga-sanbyakunen-mae-no-boukun-ouji-ni-tensei-shiteshimaimashita-zensei-no
Please, need help searching for this series:
The main character is male.
He realizes he has become the...