Nova Byzantium

After massive climatic upheaval, few pockets of civilization survive in a new Dark Age. Nova Byzantium, the world's last empire, contracts with Alkonost mercenaries to defend its territory and interests. Above this terrestrial chaos, in the orbital city of Al Fadah Madina, an Islamic caliphate attempts to preserve mankind's heritage by employing "archivists"-agents who scour the dying Earth to collect technological artifacts.
A former Alkonost mercenary, Uri Vitko, is one of their best archivists-at least as long as he can manage to please the caliphate, avoid the empire, and stay alive .