Guardians of Hellfire by Elizabeth Hartwell

One strong woman. Four sexy Guardians sworn to protect her. A raging hellfire that’ll test their bond.
Within minutes, everything Eve Carter thought she knew about her life was eradicated by a volley of Hellfire.
She’s being called a Demon. It shouldn’t be possible. No one has ever possessed both Demonic and Fae magic before. But the fury behind the power Eve unleashed says it’s very real.
For as long as Eve can remember, she’s been the hunter when it came to Paranormal justice.
But now she’s the hunted.
Cole, Noah, Jacob, and Tyler would do anything for their mate, but if they’re going to survive this test, it’ll take the strongest magic of all.
Magic of the heart.