Opposition by Jennifer Armentrout

Book five of The Lux series.

Katy knows the world changed the night the Luxen came. She can't believe Daemon stood by as his kind threatened to obliterate every last human and hybrid on Earth. But the lines between good and bad have blurred.

Daemon will do anything to save those he loves, even if it means betrayal. But when it quickly becomes impossible to tell friend from foe, and the world is crumbling around them, they may lose everything to ensure the survival of their friends…and mankind.