Blackened Death Metal is a subgenre of metal music that combines elements (ideological or otherwise) of black metal and death metal. Blackened Death is usually confused with black which is understandable however there is a noticeable difference between black and blackened death. Blackened death metal may commonly utilize lower tuning than used in conventional black metal however still uses the trademark alternatively picked minor chords. You really could think about it as black metal with more bass or lower pitched black metal. Blackened death is also usually far more satanic in lyrics and imagery than standard death metal and it is also a little more thrashy. Blackened death metal is an excellent hybrid genre because it combines the most evil with the strongest and puts it into one animal, so to speak, resulting in the most serious possible music that everyone would find either scary or badass with no amusement whatsoever.
Belphegor and Behemoth are some of the most prominent Blackened Death metal bands.
There needs to be more Blackened death bands out there.