Battle for Souls — Ciara Knight

The entire series in one boxed set.

Book I: Rise From Darkness
After witnessing the death of her mother, Gabby Moore suffers with psychotic delusions. When fallen angel Alexander Lohr reveals she's been marked by a demon, she must make the ultimate choice or lose her mind. She can fight alongside her father, an earthbound hunter killing fallen angels and demons, give into the demon blood coursing through her veins and join the underworld, or save the man she loves from both.

Book II: Fall From Grace
Gabby Moore's powers emerge years too early due to adolescent hormones, complications with loving a fallen angel, and constant demon attacks. She is forced to deal with the guilt of believing she murdered Alexander's “mother,” while trying to stop the demonic war before it begins. Only the love and acceptance of friends, family, and her beloved Alexander can save her from turning to her demonic side.

Book III: Ascension of Evil
Gaby Moore fails to stop a demonic war which released condemned ancient angels and Lucifer's minions to Earth. When all hope is lost, Herak, an Ancient sentenced to eternal solitude for starting the first demonic war, pledges to save the world. But is he really reformed and ready to fight, or will he betray Gaby and Alexander forcing them to sacrifice their love and each other to save the world?