Sweet Ruin is the second Kresley Cole book I've read and I enjoyed it very much. Ruin is an Archer and a spy for the Morior. Jo doesn't know what she is, just that she came back from the dead and only eats blood, but has other strange powers that vampires don't normally have. 
 The two collide in New Orleans where Ruin is after Nix, a seer, who also happens to have Thaddeus, Jo's brother. They are a very engaging couple, outwardly brash, but secretly with a lot of issues because of their pasts. They're a good match and the story moves right along in a good read if you like paranormal romance.