Whirl (Ondine Quartet #1)

Seventeen-year-old Kendra Irisavie is an ondine, a water elemental caught in the middle of an ancient war with the Aquidae, immortal dark demons who will stop at nothing to destroy the fragile balance of the Elemental world. Alone and with no one to trust, she must now navigate through a dangerous new world, face the temptations of a forbidden romance, and remain true to her duty and destiny.