This reminds me a bit of Sherlock Holmes. I might be a little sketchy on the details, but some of Sherlock is under public domain, and some of him from later stories is still under the original copyright protection and belongs to Arthur Conan Doyle’s estate.

Apparently the early Sherlock in which he’s more wooden and emotionless is public domain, but a kinder and gentler Sherlock was in the stories that are still copyrighted, which is why you don’t see that version of Sherlock in the current iterations.

They sued the new Netflix version with his little sister Enola because of this and it was dismissed but I believe they settled.