Considering it's the norm when you aren't doing something genre typical to take two ir more genres and just smoish the names together. This way you get things like blackened death metal (black plus death) or epic gothic power metal (take a guess). Now smoosh those teo examples together and you get something like blackened gothic melodic death metal. See that there, now we get into the transformative properties of metal subgenres. Death metal with a bit more melody and structure, which power metal has in spades, becomes melodic death metal.
Fun isn't it? Also I may have bullshitted together half of the above. But it is a real thing