Kevin Feige was speaking at the New York Film Academy and was asked about how the decisions are made regarding which characters get introduced into the universe and when. He responded that sometimes, in the case of Black Panther, it's a necessity of the story. Captain America: Civil War was in need of a an antagonist for Captain America, because during pre-production Robert Downey Jr. wasn't actually under contract to play Iron Man again and there was a possibility the movie would happen with out him.