House of Cards: Royal Angels by Jessica Lynch

To the humans, Raziel seems like a god on Earth. If only they knew how close they are…

Because Raze isn’t a god — he’s an angel. Cast out of Heaven millennia ago, Raze and his two brothers have survived banishment by relying on each other. From shepherds to farmers to kings, these days the trio of fallen angels are right at home in Sin City. Running a casino that caters specifically to the different factions of paranormal beings, they haven’t given up on a return to the celestial cities. Without their key — a literal golden key — to the pearly gates, however, that return is impossible.
That’s not their only trouble. Despite being considered royalty among their kind, the three angel princes harbor a secret. For longer than they’d liked to admit, their angelic senses have been fading, their power draining. They still control their corner of Las Vegas easily, but Raze can tell something’s wrong.
And then he meets Becca and he knows it.
The beautiful redhead tempts him like no other. With her lovely grey eyes and angelic smile, he doesn’t want to believe what his waning senses tell him: that she is a demon… and his fated mate.
For Becca, visiting the infamous Angels of Sin City was her last resort. She’d hoped to trade information for protection because, after betraying Lucifer, she would need it. But when she sits down with the imposing Raziel, she realizes she’s in over her head.
And no amount of praying is going to save her now…