The God Machine - The Evolved, #7

His brain resurrected by the Evolved, weaponized against Arvada Sattar, and fitted with a Grinder body, Sahan Kotori now commands the Grinder forces. Haunted by the sound of her laughter as she betrayed him, he vows to cast her down into the Terror Barrier, and transform that laugh into one eternal scream. Through space battles and hand-to-hand combat amid colonies and boarded ships, Arvada hunts Sahan in turn.
Though she dreads killing him, the war against the Evolved can only be decided by which of these former lovers destroys the other first.