This is discussion archived from a time before the current discussion method was installed.
Working Title: The Heavy: From YKTTW
Idle Dandy: There's no reason to limit this to heavies who are not the Big Bad. They'll overlap a lot. The difference is that this is a theatrical term. It's like "the lead" or "leading man." It's referring to a role played by an actor, a villain with a lot of screentime. That's why it's in the casting section.
Probably most heavies will be the Big Bad, but you can have a Big Bad without being The Heavy. A Big Bad doesn't have to ever be seen. The Heavy is all about being seen, because it's about the role.
In that respect, the term probably doesn't apply to books, comics, or other media without live or voice actors. You wouldn't say the main character in a novel is "the lead," so you wouldn't say the main villain is "the heavy."
