In the metal music community there are multiple branches of metal music. One of these branches is Death Metal. 

People have taken the gory and violent style of metal and assumed that they were part of Satanism worship.
Songs and albums have had different meanings like any other genre of music. Songs about love, hate, happiness or sadness have all been written by various artists.
MelodicA growled vocal, double bass drumming and crazy guitar riffs fits this at home with the metal community. Bands like At the Gates, In Flames and Dark Tranquillity have made this famous.
TechnicalTechnical is a break off of progressive rock and classical music. It has its own song with lots of harmonies and melodies. The different feature you will find is their uncommon time signatures. Bands like Opeth, Edge of Sanity and Cryptosy fit into this category.
DoomParadise Lost, Winter and My Dying Bride have brought both worlds of doom metal together, giving you a slower tempo of metal music.
BlackenedBands like Behemoth, Blasphemy and Zyklon have brought out this fairly new
subgenre of music called Blackened. These bands have both features from the black metal world, so they called it Blackened.
Goregrind / DeathgrindThis is probably the fast tempo metal music category. They have very complex intensity and speed in their music. Circle of Death Children, Cephalic Carnage and Brujeria have kept the growling singing to stay in the metal family.
DeathcoreSalt the Wound, Job for a Cowboy and Suicide Silence are some of the bands that have created this new sub genre of music called deathcore.
Keep the fast intensity as of deathgrind, but giving you more metal elements like deep growling vocals.
Future of Death MetalDeath metal isn't going anywhere or going to die out. It is only getting better and more popular. Some bands are getting to public radio and are connecting to a different crowd.
