Daimonion

Dati Amon wants to be free from his satyr master and he hates his job--hunting human children who display demon balefire. Every hunt has been successful, except one. A thwarted attempt ended up as a promise to spare the child of a white witch, an indiscretion Dati hopes Master never discovers.

But Master has devilish machinations of his own. He needs human-demon hybrids, the Daimonion, to raise the Dark Lord to the earthly realm. If Master succeeds, he will be immortal and far more powerful.

...