Seven Archangels: Annihilation (The Seven Archangels Saga, Book 5‪)‬

All angels have known since their creation that they cannot be killed, but now Satan is convinced the impossible can be done. Demons abduct and are able to tear apart the Archangel Gabriel's soul, leaving the angels in stunned grief. If Heaven isn't forever, where is God's justice? Can Gabriel be saved from the void? How can Michael stop Satan from winning this final victory against God?