They Killed My Child. I Burned Heaven.

The phoenix goddess wants to stay with the mortal man she has fallen in love with. She had come down from heaven to look for her kin, and the love came unplanned. Heaven's law forbids it, and she has broken the law without knowing. The man sitting on the throne of heaven holds it without right, and a woman has been passing herself off as the goddess. The two of them use the breach to set a trap for her. She loses her husband and her child to it. What she felt for the man turns into hatred for the two who did this. At the point of death her body burns and comes back, and the phoenix bone in her wakes. She takes a celestial mirror and offers it as her stake to the god of war, the one power the false emperor is afraid of, and asks for an alliance. He is cold and hard to deal with, and he agrees. The two of them go to war against the court of heaven together.