The phrase "main villain" refers to the most important and prominent antagonist or bad person in a story or movie. They are usually the primary source of conflict or opposition for the main character or hero. Full definition
There was almost a different main villain for the first Iron Man movie. (flickeringmyth.com)
Main villain after villain appears with some sort of disgusting physical complication. (mediamikes.com)
Sure, there are a plethora of television programs and movies based on comic book series, but how many of those movies and television programs have the privilege of creating new main villains? (jamiex66.com)