Wicked Abyss by Kresley Cole

This fairy tale doesn't end with a kiss... A spellbinding Immortals After Dark tale from #1 New York Times bestselling author Kresley Cole!
The terrifying king of hell...
As a boy, Abyssian "Sian" Infernas had his heart shattered by a treacherous fey beauty who died before he could exact vengeance. Millennia later, a curse has transformed him into a demonic monster--just as she's been reincarnated. Sian captures the delicate but bold female, forcing her back to hell.
Meets his match.
Princess Calliope "Lila" Barbot's people have hated and feared Abyssian and his alliance of monsters for eons. When the beastly demon imprisons her in his mystical castle, vowing revenge for betrayals she can't remember, Lila makes her own vow: to bring down the wicked beast for good.
Can two adversaries share one happily-ever-after?
As Calliope turns hell inside out, the all-powerful Sian finds himself defenseless against his feelings for her. In turn, Lila reluctantly responds to the beast's cleverness and gruff vulnerability. But when truths from a far distant past are revealed, can their tenuous bond withstand ages of deceit, a curse, and a looming supernatural war?
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