Whether the protagonist of a time-travel novel traveled from the immortal world or from the modern world depended on the plot and direction of the story. Here are some possible ideas: - If the protagonist is an immortal who has encountered a bottleneck in his cultivation and then transmigrated to a different world, he may use his existing skills and experience to adapt to this new environment and compete or cooperate with other immortals. This kind of plot usually involved the history and culture of the immortal world, and there might also be some mysterious elements. - If the protagonist is a modern person who travels to a different world, he may discover that he has modern skills and knowledge, which he can use to adapt to the new environment and establish connections with others. This kind of plot usually involved the history and culture of modern society, and it might also have some sci-fi or fantasy elements. No matter which plot you choose, you can create a unique world for the readers to immerse themselves in after the protagonist transmigrated. Some common elements such as magic, magic, myths, legends, technology, modern society, etc. could be considered to add color to the protagonist's world.