After demons prove incapable of impregnating the fallen angel Astariel so Caerophon can acquire a nephilim, it's decided that Astariel will impregnate a demon instead. Malachi, most fertile of Caerophon's concubi, in particular.
They succeed and Malachi is soon heavy with child and more alluring than ever to egg-heavy Astariel, who can't get enough of his pregnant pussy.