Atmospheric black metal is a sub-genre of black metal which relies on heavy incorporation of atmospheric, sometimes even dreamy textures, therefore moving away from its parent into a less aggressive direction. Atmospheric black metal often features synthesizers or classical instrumentation, typically for melody or ethereal "shimmering" over the wall of sound provided by the guitars. The music is usually slow to mid paced with rare blast beat usage, without any abrupt changes and generally features slowly developing, sometimes repetitive melodies and riffs, thus providing another notable distinction from its parent and other black metal sub-genres. Subject matter usually concerns nature, folklore, mythology, and personal introspection.