81 Layers of Ember

The Tower has 81 sectors. Jack was born in the bottom one—a scrapyard where defective clones and broken machines go to die on schedule. He wasn't supposed to wake up. He wasn't supposed to fight a Sweeper with his bare hands and win. And he definitely wasn't supposed to find a neutron-star-density weapon called the R.U.Y.I. Rod, waiting centuries in a frozen weapons lab for a hand to claim it. But the system made one mistake: it gave him nothing. No serial number. No expiration date. No programming. Just a tactical combat chassis and a question none of its seventeen million simulations could answer—what happens when a null-subject decides he doesn't want to die? Now Jack is climbing. Sector by sector. Building a coalition of things the Tower wants dead. Hunting the Full Kernel—the original operating system that can delete the AI god at the center of everything. The Tower is watching. The gods are nervous. And somewhere in the upper sectors, a young data-keeper named Xuanzang is about to learn that the pilgrimage he's been studying his whole life requires one thing he didn't expect: The most dangerous clone in the Tower, walking beside him.