There is a question, irrespective of copyright, of how much ownership any creator has over characters once they've introduced them into the world. Fan fiction is a very real thing, and the demands of corporate interests necessitate licensing and spin-offs and any number of gambits that turn a creative property into a larger commercial enterprise. Rights are rights, of course, and rightsholders can exert control over how or if their creations are used for so long as they own them. But what happens when work falls into the public domain, at least partially?
That's the fascinating question at the heart of a lawsuit brought by the estate of Sir Arthur Conan Doyle against Netflix for its new film Enola Holmes, specifically over how the film depicts Doyle's iconic private detective Sherlock Holmes. The Doyle estate is alleging that Netflix and the film are in violation of the estate's copyright on the character in their depiction of Sherlock Holmes in the film.
If you're vaguely remembering reading about Sherlock Holmes being placed into the public domain, you're not wrong. A district court judge in Illinois affirmed the status of the majority of Doyle's works as no longer copyrighted, but that only extended to works published before 1923; everything created after that point was, and is, protected by copyright and property of the Doyle estate.
Where the story becomes further complicated is in the origins of the Netflix film. Enola Holmes is based upon a series of stories written by Nancy Springer and starring the detective's teenage sister. And as with any work interpreted by more than one creator, the Sherlock Holmes character is invariably changed based upon a new author's ideas and interpretations. But the public domain version of Sherlock Holmes, the one freely available for use by Springer and others, is famously unchanging. Springer's Sherlock is more emotive and caring, and more respectful to the people in his life, particularly women, not dissimilar to the changed and changing Holmes of Doyle's post-1923 stories.
In portraying a more human Sherlock Holmes, the Doyle estate is arguing that Netflix, and by extension Springer, are violating the copyrighted works still under their control. But it's difficult to make the case that an author is entitled to use a character but not permitted to change it in any significant way or add any depth beyond what little is provided in the early Holmes stories. It admittedly seems difficult to figure out how to balance those rights given the ownership divide, but going after every creator that seeks to take one of fiction's most famous characters and make him their own is probably not a particularly productive tactic.