"A young girl, no older than fourteen, her hair dyed green and orange and pink, stared at them as they went by."

The girl mentioned here, sitting beside a mongrel dog, is Delerium from Neil Gaiman's The Sandman graphic novels. In keeping with the mythical beings Shadow is coming across, Delerium is one of the 'Endless,' beings who are older than gods and will be around long after gods and humans have gone.