MTL - Tales of Herding Gods - Chapter 41 Push knife

The first time I realized that I ‘couldn’t die’ was during a practical training exercise in my third year as a hero cadet.A beast suddenly leaped out of the bushes and tore into my neck.‘How did I come back to life?’Yes, I came back to life. I didn’t die.And now, after hundreds, even thousands of years, I was still alive. Only I had survived.“But now… it’s finally over.”After wandering for millennia, I thought I could finally put an end to this long existence…“Dale! Dale Han! How dare you sleep during my class? You’ve got some nerve, don’t you?”“…Huh?”But what awaited me at the end of my long existence wasn’t a period, but a repeat sign.

A skilled but unfortunate modern-day assassin was killed in a freak accident. However, he soon found himself summoned to another world by an evil wizard, who had him possess the body of a boy as an experiment. After successfully planning the evil wizard’s downfall, he used the wizard’s body as a springboard to gain influence and power in his new world.

- Description from Novelupdates

High-school student Koremitsu Akagi finds himself attending the funeral of Hikaru Mikado, who had died in an accident during Golden Week. He’s not sure why he’s there, as he only exchanged a few words with Hikaru at school. However, Hikaru doesn’t seem to be completely gone from the world, as he comes back as a ghost in order to fulfill a promise to Aoi Saotome, his fiancée. Since Koremitsu is the only one who can see him, he asks him to carry out his promise in his place.

Complying with his request, Koremitsu tries to fulfill Hikaru’s promises to the rest of his “girlfriends”, helping them overcome past misunderstandings and repair broken relationships.