Legal Question in Entertainment Law in California

Characters themselves can not be copyrighted or trademarked in the United States. However, the look of the characters--the way they're drawn, their costumes, merchandising, etc. can be. From what you described, it sounds as if the costumes would be more of the homemade imitation-type than a detailed knock-off of the look portrayed in the Warner Brothers movies.

Among the things a court considers in trademark infringement cases is whether there is confusion in the marketplace--is an average person going to think that your product originated from (or was sanctioned by) the owners of the Batman trademark?

Another consideration might be whether your use of the term Batman and the Batman imagery diminishes the value of the authentic Batman goods. That might be a tougher call if you're disparaging the trademark or suggesting immoral behavior on the part of Batman. If, however, the imagery is somewhat generic role-playing and there is no actual reference to 'Batman" and 'Catwoman," there would be less cause for complaint.

It is always a good idea to have an experienced attorney take a look at your script before you incorporate well-known trademarks. He can advise you on whether changes would be needed or whether you should obtain a license to use the mark. It is NOT a good idea to approach a trademark owner yourself before you are sure you need their permission--that can backfire.