Locklands (The Founders Trilogy #3) by Robert Jackson Bennett

A god wages war—using all of humanity as its pawns—in the unforgettable conclusion to the Founders trilogy.

Sancia, Clef, and Berenice have gone up against plenty of long odds in the past. But the war they’re fighting now is one even they can’t win.

This time, they’re not facing robber-baron elites, or even an immortal hierophant, but an entity whose intelligence is spread over half the globe—a ghost in the machine that uses the magic of scriving to possess and control not just objects, but human minds.

To fight it, they’ve used scriving technology to transform themselves and their allies into an army—a society—that’s like nothing humanity has seen before. With its strength at their backs, they’ve freed a handful of their enemy’s hosts from servitude, even brought down some of its fearsome, reality-altering dreadnaughts. Yet despite their efforts, their enemy marches on—implacable. Unstoppable.

Now, as their opponent closes in on its true prize—an ancient doorway, long buried, that leads to the chambers at the center of creation itself—Sancia and her friends glimpse a chance at reaching it first, and with it, a last desperate opportunity to stop this unbeatable foe. But to do so, they’ll have to unlock the centuries-old mystery of scriving’s origins, embark on a desperate mission into the heart of their enemy’s power, and pull off the most daring heist they’ve ever attempted.

And as if that weren’t enough, their adversary might just have a spy in their ranks—and a last trick up its sleeve.