Okay, this one was legitimately tough. How do you decide between Mercyful Fate and King Diamond? Ultimately the decision was due to the massive influence Mercyful Fate has had on the formation of metal. That and the fact that Melissa and Don't Break the Oath are all-time metal classics with tons of great songs. This is not to say anything disparaging about King Diamond's solo work, just that Mercyful Fate's early work is so influential that King Diamond could not fill those shoes.