His Wings by Aya DeAniege

Michael and Raphael have been fighting since the beginning of time. Their views on Earth and the people who reside on it vary greatly, and they quote that as the reason they fight. Neither questions whether their sins against their Father might be their eternal struggle.
For Michael, life on Earth had been a blessing until humans arrived and Samael messed it all up. He wants to raze all of civilization to the ground and start over. Without humans or any other sentient race for demons to possess.

Raphael believes humans to be a curiosity. They weren’t led astray by Samael during his split, only one of them was, they are merely products of the choices of other humans who came before them. He believes the cycle can be broken and humanity saved, even if he has to do it one human at a time.
When Grace entered their lives three years previous, they saw in her redemption. They began scanning the faces of every human they passed, wondering if that one was their redemption. And then they spotted their opportunity.

A woman named Sera, who has the wings of an angel tattooed on her back. The only trouble is, both are certain she was made for them.
Their fight could very well herald the end of times. Can they learn to put aside their petty fight for the woman they love?