Ties of Blood and Silver — Joel Rosenberg

Elwere - city of rainbows, where the fortunes of the planet Oroga are concentrated in the grasping hands of the privileged few. To David, stolen from Elwere as a baby and raised as a thief of the Lower City, it is a dream of paradise, a treasure trove to which he must find the key, no matter what the cost...

And Eschteef - a schrift of the jewel-and-precious-metals schtann, twice the size of a human, more than twice as strong, with frightfully glowing eyes and rows of needle-sharp teeth. It, too, has a dream, a dream of which David has suddenly become the crucial focus. And once a schrift has chosen, nothing can change its path.

Elwere or the Alien - two different roads to the future, leading to either wealth and power - or death...