Because metal isn't just a genre of music, it's a way of life
They can't stop us let 'em tryAlso known as headbanger, thrasher, or hesher, the metalhead is a character that started showing up in movies and television shows in the 1980s. As the title implies, he (and it almost always is a "he", although female metalheads do exist) is very passionate about hard rock and heavy metal music and is not shy about expressing it. The metalhead can usually be identified by any combination of the following: long hair, tattoos, piercings, a black t-shirt baring the logo of his favorite band, a black leather motorcycle jacket, tattered denim jeans, or a denim vest adorned with pins and patches. They are also known for using the "heavy metal horns" hand gesture as a way of showing their approval for something. In popular media the metalhead is often portrayed as being not very bright. He usually has a menial job and dreams of one day being in a successful band. He likes to say "dude" and "awesome" a lot. Although he doesn't have a lot of book smarts, his knowledge of heavy metal is staggering and he can debate for hours what bands should and should not be considered "metal." Other stereotypical things that the metalhead loves are muscle cars, motorcycles, beer, horror movies, violent video games, and (depending on the portrayal) marijuana.
For heavy metal we will die!
-Manowar, "Die For Metal".
Examples:Anime and manga