Fox's Tongue and Kirin's Bone

Humanity is dying, hunted to extinction by creatures of legend. One boy was born to save them all.
That boy just got knifed in the back. He looked a bit too much like Aaron, you see.
Now it's Aaron's job to step up, lest his death correct that little mix-up. But Aaron's skills as a street rat run more towards stealing and stabbing than saving. The more he learns of what brought dear dead Markus to that fatal alleyway, the more he has to wonder just what the world's savior was really up to the night the wrong boy died.