The materials the character is embodied in are automatically protected, but to specifically protect the character separately you may need to register it as a trademark. A knowledgable discussion is linked below.
Depending on how "thinly veiled" it could be judged an infringement of both a copyright and trademark.
Sherlock Holmes is a fictional character.
Yes, he was a fictional character.
The character, Rose, in the movie Titanic, is a fictional character.
Athos - fictional character - was created in 1844.
Zatoichi is a Japanese fictional character created by the novelist Kan Shimozawa. This fictional character is a blind masseur, gambler and a swordmaster.
No, he's a fictional character.
She is a fictional character.
There are no special provisions for fictional characters in current US Copyright Law. They are protected just like any other original artistic work.
Scrooge was a fictional character who did not believe in Christmas. He is from the Christmas carol.!
Dave Lister - fictional character - was created in 1988.
Christine Williams - fictional character - was created in 2009.