Attempt to answer the question, which I think is an interesting one.
-From a genealogical point of view, metal as an art form is rooted in Europe.
-Content-wise, it has its obvious precursors in Antiquity and Romanticism.
-But in this regard, the typical warlike spirit of metal is an atavism, whose essence is probably found in any societies' cultural expression as well- at some point in time.
-Present day, the cultural relevance of metal probably extends to wherever society decayed to the point of self-destruction, a tendency to which metal is a reaction.
Indeed, in a pluralistic society I think elective cultures such as those that surround styles of music like heavy metal are, if anything, more legitimate than other forms.Article
They show our capacity to build our cultural frameworks out of the things that matter most to us rather than simply accept what has been foreordained as having value.
So i'd say metal is not an 'established multiculture', but an elective culture (/second nature), in which participation isn't restricted by geography/ethnicity beforehand.