Begin by getting a clear understanding of the world in which Christopher Stratos exists. If there are specific rules, like magic systems or social hierarchies, make sure you know them. After that, think about the conflict or goal for your fanfic. Is it a battle against a powerful enemy? Or is it a personal struggle for him? Outline your story with a beginning, middle, and end. Write down some key scenes and then start filling in the details as you write the actual fanfic.
Well, to start your Christopher Stratos fanfic, you should immerse yourself in his story. Read all the official materials related to him if there are any. Listen to his dialogues carefully to get his voice right in your writing. When you start writing, try to put your own spin on things. Maybe introduce a new concept or a different perspective on his character. Don't be afraid to break some rules as long as it makes for an interesting story. For example, if he's usually seen as a hero, you could write a fanfic where he has to make some morally grey decisions for the greater good.
First, study his character traits. Know what makes him unique, like his skills, his personality quirks. Then, come up with a basic plot idea. It could be something as simple as him helping a neighbor or as complex as a multi - world adventure. Next, create some interesting characters to interact with him. They can be new or from the existing universe. Start writing and don't worry too much about perfection at first.