Beauty Awakened by Gena Showalter — book slip

Koldo is a powerful angel, scarred and driven by vengeance against those who took his wings. His life is consumed by hatred, threatening his place in the heavens. Nicola Lane, a human with a fragile heart, becomes his last hope. As demons pursue her, Nicola's unexpected strength and resilience offer Koldo a chance at redemption. But saving her may require the ultimate sacrifice.

Second in the Angels of the Dark series.