Noun
extreme metal (uncountable)
(music) Any style of modern heavy metal, especially thrash metal, speed metal, doom metal, black metal or death metal.
To do an extreme metal record is something that is well within my capacity as a musician to write stuff out of the box, write stuff that's probably more extreme than the band I'm in at the present time, and it's something that needs to come out of me one way or another. Phil Anselmo
Extreme metal bands (especially black metal bands) and Goth rock groups have extensive leather clothing. Source: Internet