It's a claim I feel pretty comfortable with. It's at the beginning, often in the first few sentences, in nearly every wiki or article about the guy after all. Every one of them that isn't specifically talking about Arthur Fleck anyway.
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By that logic, his name is even more defining, and Arthur actively went by Joker in the movie.
Cuthalion's art is the prettiest art of all the art. Like my avatar.
Number of times Roland St. Jude has sworn revenge upon me: 2