Perfect Vision (Book 3 of The Fusion Series) - The Fusion Series, #3

Roxie Sebastian's life is a mess. She's struggling with the emotional explosion that's the aftermath of fusing with her angel soul. Her relationship with her parents is cracking under the strain of too many lies. And even though she and her friends have saved the world (more than one of them, actually) they also have let in a being of unimaginable power and unknown intentions. The circumstances of Roxie's birth have made her a completely unique being.
Every time she uses her abilities, it increases her own power. As a series of visions show her truths even the other angels and shadows didn't know, new threats close in. She must unite allies and enemies in a race to save her father from possession and the world from invasion. She can't succeed without the help of Gaia, the most powerful angel, who almost killed her 18 years ago. But that help will come at a most terrible price.