Time-travel yarn, in the ultra-violent tradition of The Skinner (2003).
Centuries from now, the eugenicist-supermen Umbrathane are fighting a destructive war with the super-supermen Heliothane. Cowl, a genetically modified Heliothane, allies himself with the Umbrathane and time-travels back to the remote past, before higher lifeforms evolved. What he does there isn’t entirely clear, but engineer Goron and the other Heliothane want Cowl dead. Time is multiply tracked, with every change in a timeline giving rise to multitudes of new tracks (which is why Umbrathane and Heliothane can’t use time travel to wipe each other out). A monstrous, insatiable creature called the Torbeast, partly controlled by Cowl, sheds temporally active scales called “tors.” These tors attach themselves parasitically and irremovably to humans and drag them into the past to meet Cowl, to whom their DNA is of interest. Not so far in the future, meanwhile, teenaged, drug-addicted whore Polly helps warrior Nandru tussle with programmed government assassin Tack over a McGuffin. Though Tack kills Nandru, an intelligent device containing Nandru’s mentality implants itself in Polly, and both Polly and Tack acquire tors. Polly’s soon cures her drug addiction but causes her to eat voraciously while dragging her back through WWII, past Henry VIII and the Roman Emperor Claudius into the Stone Age. Traveler, a Heliothane, captures Tack, rebuilds and reprograms him, and aims him at Cowl.
Asher’s time-travel rationale holds up, amid the crackling energy and slam-bang action. The big drawback here: it’s impossible to understand the motivations of the movers and shakers—Asher’s belated explanations don’t help—and thus, absent noteworthy or appealing characters, hard to care about what comes next.