Develop the character. A well-developed character that cannot be mistaken for any other character is a must when copyrighting a story character. A complete physical description, along with a fully developed personality and set of characteristic behaviors, will assist you in copyrighting your character.
Copyright the story in which the character appears. Some characters are copyrighted with a story if the character is well developed and has a very specific appearance. This is not all-encompassing for copyrighting characters, but it can give some protection. According to the U.S. Copyright Office, your work is "under copyright protection the moment it is created and fixed in a tangible form that it is perceptible either directly or with the aid of a machine or device." This means that technically your work is protected by copyright from the moment you write your story or novel. However, you will need to register your work with the U.S. Copyright Office if you plan to sue someone for infringement of your copyright.
Create a picture of the character. Courts are more likely to allow copyrighting of a character that has a specific image that goes with the character. An artist who draws the character according to the author's description can create a picture for the courts to look at as a representation of what the character is intended to look like, and therefore a copyright for the character can be more easily defended.
Make the character's name or identifying phrase a trademark. Although characters and stories can have expired copyrights, a character trademark does not expire, and it can be easily proven in court if others use it.