Whether MSA are real stories is not straightforward. Sometimes they draw inspiration from real life, but are embellished or fictionalized to make them more engaging or to fit a certain narrative.
Well, it's hard to say for sure. Some MSA stories could be real, reflecting actual happenings or people's true accounts. But there's also a possibility that they're made up to captivate the audience and take them on a fictional journey.
MSA is typically not based on true stories. It's more about creativity and constructing fictional plots and characters to entertain the readers/viewers. However, some elements might draw inspiration from real-life situations but in a very indirect way.
It is currently impossible to confirm whether the novel or the music came first because this question involves legal issues such as copyright and intellectual property rights. We need to understand the relevant laws and regulations before we can answer. However, according to what I know, The World was originally a novel rather than a video or music, but it was later adapted into a TV series. Therefore, it could be said that the original form of the world was a novel rather than a video or music.