She was dragged into a school built to turn students into infrastructure. Talla Rook has spent her life clawing breath out of Low-Tide. Then one wrong surge of forbidden power tears her out of the gutter and into the Obsidian Citadel, a brutal military college where gifted bodies are trained, ranked, and quietly discarded. Inside the Citadel, survival is a blood sport. Cadets vanish. The city calls it service. Talla calls it what it a filtration machine dressed like honor. The one man who sees how dangerous she is might also be the only reason she survives. Commander Soren Valek is cold, precise, and loyal to the system that feeds on her kind. He should be her enemy. Instead, he becomes the sharpest tether she has. When the first culling turns catastrophic, Talla survives something no one should survive. Now the machine knows her name, and it has found the one place to cut her. Perfect for readers who love Fourth Wing, Red Rising, and dark academia with body-horror magic.