Sam Raimi and Bruce Campbell
Obviously these two were invented before The Evil Dead. And technically Sam Raimi invented The Evil Dead and not vice versa. But if he hadn’t, then those good Tobey Maguire Spider-Man movies would have been directed by Michael Bay or, worse, the Paul Anderson who makes all the Resident Evil films.
Meanwhile Bruce Campbell might not have even become an actor. Think about that. The guy nobody doesn’t like, completely absent from Escape from L.A., The Adventures of Briscoe County Jr., Maniac Cop, the terrible McHale’s Navy movie, the TV remake of The Love Bug, Bubba Ho-Tep and whatever Burn Notice is. Also? No My Name Is Bruce, the one where he plays himself being mistaken for Ash, his character in The Evil Dead. At all.