I will scare the hell out of you children.
I'm pretty much in the minority when it comes to music here.
Here's a musical version of Hetalia, the Nordic countries in their black metal garb. Norway is the most well-known for the genre, but there were a handful of Sweden black metal bands as well during the 1990's. There weren't as many Finnish bands, but I added Finland in there because I thought it would be funny to see Tino in corpse paint looking like a bad ass, it's so out of his character XD
SO!
Let me give you a small history lesson of one of the most controversial sub genres in metal, and perhaps of all music. Black metal is a sub genre of metal, characterized by low production sound that gives it the raw, primal feeling, with a lack of bass and a emphasis on atmosphere. The guitar is distorted, using high gain and treble, having minimalist compositional structure, rhythmic, cycling riffs, tremolos, and arpeggios. Much dissonance is present, but the rendering of melody and harmony in songs, as well as the use of bright major chords, have also been present, as an example in many Emperor songs. Vocals are usually harsh, anguished shrieks, or are rasped and howled, depicting darkness, melancholy, and severity. Drums are characterized by blast beats, or rapid snare/cymbal stokes along with bass drums (sometimes double pedal), creating a wall of sound. Black metal music is the epitome of anti-mainstream, with its extremism, rawness, and iniquity.
There were two "waves" of black metal, the first consisting of bands like Venom (UK), Bathory (Sweden), Baphomet (US), Abruptum (Sweden), Marduk (Sweden), etc. These were considered the prototypes of black metal during the 80's. The second wave (early 1990's) consisting of Emperor, Arcturus, Enslaved, Mayhem, Burzum, Immortal, Ulver, Gorgoroth and so on. Most of these bands are from Norway, but there are some outliers like Rotting Christ from Greece, Antichrist from Canada, Nocturnal Feast from Finland, and early Sigh from Japan.
The prevailing schema of the genre's image is that of a dark one, and rightly so. The early 1990's was hell wreaked onto the quiet and unaware Scandinavian lands, effervescent of murder scandals and church burnings, amongst other antisocial activities, all that had connection to the genre. Most of black metal was Satanic or pagan in lyrical themes, but was also Romanticist in nature, depicting philosophy, Norwegian mythology, literature, folklore, and tales of the Vikings. Nature and fantasy also play a role in themes. National socialism was also a present theme in some black metal bands, but not all uphold this ideology. Today's black metal has expanded more on ambience, atmosphere, and genre crossovers, but there are a few that catch the flame of their predecessors, and keep that fire burning.
To learn more about black metal, you can google that shit, or visit these sites:
American Nihilist Underground Society:
http://www.anus.com/metal/about/black_metal/
A.N.U.S black metal and mythology:
http://www.anus.com/metal/about/black_metal_mythology/
The Metal Archives:
http://www.metal-archives.com/
A recent black metal documentary, "Until the Light Takes Us": http://www.youtube.com/watch?v=2u1ltnthAcA&feature=results_video&playnext=1&list=PL55F94CC2379E2A72
I used Immortal for the references.