First, you need to decide on your main character. It could be an original character or a re - imagined version of an existing X - Men character. Then, think about which X - Men characters will be part of the harem. Next, come up with a plot. Maybe it starts with the main character arriving at the X - Men school and slowly getting to know the others. Don't forget to give your characters unique personalities and relationships.
Well, when starting an 'X Men harem fanfic', you should first outline your story. Decide if you want it to be a long - term epic or a short and sweet tale. Then, focus on the character interactions. Since it's a harem fic, there will be multiple love interests. Think about how they will all interact with the main character and with each other. You can also add some unique elements to the X - Men world, like new mutants or new threats. This will make your fanfic stand out. Also, don't be afraid to experiment with different writing styles and voices to bring your story to life.
To start writing an 'X Men harem fanfic', begin by researching the X - Men universe thoroughly. Know the powers, backstories, and personalities of the characters you want to include in the harem. After that, create a setting for your story. It could be a post - apocalyptic world where the X - Men are struggling to survive and your main character becomes a source of hope and love for them. Develop the relationships gradually, showing how they evolve over time. And always keep in mind the overall theme and mood you want to convey.