I'm not so smart as y'all. I don't get the riddle. : (
I know next to nothing about Slayer, but figured it out from this line:Best Judas Priest song = Diamonds & Rust
Diamonds & Rust is a Joan Baez song.
So I presumed that "Dissident Aggressor" is a Judas Priest song.
So the challenge (from a musical POV) is to find a cover that Baez sang well, the author of same song having in turn sang a cover, who's author sang a cover, who's author sang a cover, ad infinitum. But I'm not a big fan of Baez, so there it lies. 40hz would be the man for this, he seems to be a walking encyclopedia about music - and everything else too when I think about it :-)