Santa Claus isn’t really a character, though. He’s a mythical figure. No one owns a trademark or copyright of Santa Claus. It would be like saying the tooth fairy is white. There are common depictions of Santa Claus, like the Coca Cola Santa, but those are just adaptations of a myth.
Blade, on the other hand, is an actual character, owned by Marvel. So Marvel decides what is canonical with regard to the character.