The Redeeming: Immortals, Book 5

For seven hundred years the Immortal warrior Tain was held captive and tortured by a powerful demon, and retreated into madness to escape his pain. Set free by his brothers, Tain has wandered the world, but he's drawn to Los Angeles, a city divided by demon lords and vampire masters, the death-magic creatures barely kept in line by strict rules and the paranormal police.

Samantha Taylor, detective in the paranormal division, brings down drug-selling demons and vampires who turn too many victims. One night, her stakeout of a demon club is blown by the appearance of a man with amazing power, who kills attacking demons with one burst of incredible magic.

Samantha realizes to her shock that the man is Tain, the Immortal she helped rescue, whose healing touch burns her.

Tain is back, and he needs Samantha's help. Young demon women are being murdered, and though Tain has no love for demons, he recognizes that they are innocents. He's also powerfully drawn to Samantha, a half demon, and fears his pull to her means he hasn't healed from his ordeal. Tain reveals to Samantha more about herself than she's comfortable knowing, but though she's falling for Tain, she knows he'll never allow himself to be tied to demonkind again.