User blog comment:Jacknapier10/Which characters cannot appear in the Marvel Cinematic Universe?/@comment-5350299-20140428113836/@comment-24892167-20140502153726

Kingpin is a Daredevil and a Spider-Man villain. I think both, Marvel Studios and Sony could technically use him in their movies. It's the same case as with characters like Quicksilver or Scarlet Witch, who are Avengers but also mutants, Magneto's children and members of his brotherhood.