The big four that you mentioned are metallica, megadeth, anthrax & slayer xD
the Big Five, the pirate leaders of the Alliance on the other hand are another matter. So far, only two of them have been listed in the thread, Black Fog (#2 Public Enemy) and Ice Queen (#4). Captain Adrian isn't one of them, but being #10, he's pretty close. He's not the only badass pirate in Carajol. I've purposefully not designed the other three from the Big Five because I wanted there to be space in case any member of the RP comes up with an idea for such a character.