P.O.S. is a rapper from Minneapolis. He started out his music in a punk band, and the influence can still be heard, but now he makes intelligent but angry underground hip-hop. The main thing that stands out is that his beats are sometimes crafted from chugging metal guitars (and is that double-bass I hear?). He's also a part of the Minneapolis-based Doomtree collective, which I also recommend to hip-hop fans. This was requested, but I have definitely been listening to (and posting) a lot of hip-hop recently; five years ago I never would have guessed!