Sammael's Wings

Jonathan is the only half angel and half demon in the world. Having discovered his heritage, he must now continue the battle against the demonic forces that are hellbent on ruling creation. The Archdemon Baal is one such monster, and he holds Jonathan''s parents captive.
But to succeed, Baal needs the wings of an Archangel. Jonathan and his great-aunt Sammael are the only two such angels left, but...