The Recovery of Terror Begins with a Bloody Letter

When I thought it was just an ordinary day, I woke up in a strange room and traveled to a new world. Just when I thought I would use my abilities and the differences between the two worlds to gain fame and wealth, a bloody letter that I couldn't get rid of entangled me. Just when I thought that by completing the mission of Blood Letter, I would know the way out of this world, the truth that ghosts cannot be killed was told to me by the creator of the Blood Letter mission. Now I am looking for the opportunity to become a god. If I fail, I will become the most terrifying ghost in the world. If I succeed, I will become an immortal god. Now, I leave this sentence, ghosts cannot be killed, I hope that future generations will remember it...