Album covers

For my secondary task i have to design a Digipak- So i have researched some heavy metal album covers to find out what the niche is to getting them quite right .

Obviously there is some reocurring themes with the album covers. The use of bones, demonic symbolism, crossess and celtic fonts.
There is some gothic themes inside as well.
The names of the albums are usually a play on words as well i.e "Rust in Peace". There are also some political messages like "Master of Puppets" has hands holding strings over dead soldiers. There is a consistent use of the colour black as well.