It’s relatively easy to hang a mythology on your sound when you come from, say, Norway, a place plenty of Americans consider exotic. But like many bands in the current wave of American black metal, Saint Charles’s Nachtmystium has to work a little harder. Grotty fifth-gen cassette demos are out; running your own label (in this case, emerging powerhouse Battle Kommand) and making it viable is in. Fractious sub-subgenre snobbery is out; touring with everyone from Deicide to Pelican is in. (Also in: releasing a split record with Leviathan, something that seems to be practically obligatory now. Nachtmystium’s is due in the spring.) That energy and flexibility are why their most recent album, Instinct: Decay, is one of my favorite metal albums of 2006. It reminds me of one of my 2005 favorites, the record from Leviathan side project Lurker of Chalice. Much of the icy, vicious grandeur of classic black metal remains, but the sound is expansive: Nachtmystium’s darkness has the spaciousness of an uncaring void instead of the lightless constriction of a coffin. The album has room for space-rock weirdness, goth melodicism, and occasionally some shiny, brittle folk. And it’s heavy. Don’t miss tourmates and labelmates Zoroaster, a promising doom band from Atlanta that plays second. March Into the Sea opens. a 9:30 PM, Empty Bottle, 1035 N. Western, 773-276-3600 or 866-468-3401, $8.