Question about characters
I have a question, if someone can answer it that would be great
If both studios Marvel and Fox have the rights to Quicksilver and the Scarlet Witch because they have both been in the Avengers and in the X-Men, then what is stopping Marvel from using other characters that have been part of the Avengers like Spidey, Wolverine, Beast, Namor, the FF, Sandman, and Storm
They have all been in the Avengers' roster. Also could Fox use Ms. Marvel?