The Vindication of Man — John C. Wright

Menelaus Montrose, having renewed his enmity with his immortal adversary, Ximen del Azarchel, awaits the return of the posthuman princess Rania, their shared lost love. Rania brings with her the judgment of the Dominions ruling the known cosmos, which will determine the fate of humanity, once and for all. Vindication or destruction? And if it is somehow both, what manner of future awaits them?