Wrapping up Scotland resident Campbell's bloody, furiously complicated trilogy (Iron Angel, 2008, etc.) wherein fallen gods battle the king of Hell for the keys to Heaven.
Since both sides use blood and souls as energy, how can humanity survive the conflict? In the upper world, ragged assassin Rachel Hael, blood-magician Mina Greene and her demon-dog Basilis, the drunken warrior-god Hasp and Dill the much-abused ghost decide to seek the assistance of Sabor, god of clocks, and his ability to control time itself—while behind them stalk 12 arconites, massive, invulnerable automatons controlled by Menoa, the King of Hell. Meanwhile, Cospinol, the god of brine and fog, resolves to defeat his half-brother Menoa by descending into Hell itself—so he orders his servant, the giant John Anchor, to tow Cospinol's huge, rotting skyship down into the vast breach that Menoa created in order to flood the surface with his zombie troops. Of course, nothing is what it seems. Rachel learns that time itself might be coming unraveled. And John blithely hauls Cospinol's skyship into the underworld, unaware that the insane angel, Carnival, whom Cospinol is boiling in order to extract her life-energy, has allies aboard—and burns with the need to escape and avenge her torment. Unfortunate, then, that amid this welter of gore and violence, it's difficult to decide who's on what side, or why; and, with the dearth of good or even sympathetic characters, equally tough to care about the outcome.
A disappointing denouement, even for readers readily dazzled by detail.