Circle Trilogy (abridged)

Standing on the cliffs of 12th century Ireland following the disappearance of his twin, Hoyt Mac Cionaoith is visited by the goddess Morrigan and is charged with the ultimate of tasks: saving his and all future worlds. His enemy, the beautiful but deadly vampire queen Lilith, has had over two thousand years' experience in cruelly killing and changing humans into one of her own - including Hoyt's brother, Cian.

Raised in a family of demon hunters, Blair Murphy has her own personal demons to fight - the father who trained, then abandoned her, and the fiancé who walked out on her after learning what she is. Now she finds herself training a sorcerer from 12th century Ireland, a witch from modern day New York, a scholar, and a shape changer from the mythical land of Geall, while trying to keep herself from staking the sixth of their circle and host: a vampire sired by Lilith, the vampire queen they've been charged with defeating on Samhain.

Her face, so pale when she'd removed her cloak, had bloomed when her hand had taken the sword. Her eyes, so heavy, so somber, had gone as brilliant as the blade. And had simply sliced through him, keen as a sword, when they'd met his.... In the kingdom of Geall, the scholarly Moira has taken up the sword of her people. Now, as queen, she must prepare her subjects for the greatest battle they will ever fight - against an enemy more vicious than any they have seen.