A body that does not break. The unkillable chest.

Over approximately five years post-conversion, osteoblastic upregulation converts the flexible human ribcage into what looks, on gross examination, like a continuous plate of dense cortical bone. Costal cartilage ossifies first. Then new bone fills the intercostal spaces until the thorax reads as a cuirass. Microscopically it is not a fusion. It is a tessellation of thousands of interlocking mineral micro-plates, each two to five millimetres across, separated by hair-thin seams of modified connective tissue.

Those seams are thixotropic: a non-Newtonian matrix whose viscosity surges under shear. A blade or bullet meets a structure that stiffens on impact; resting ventilation still finds eight to twelve percent thoracic excursion. The process is slow because speed would kill. The bio-voltaic drive has already dropped CO₂ output to roughly fifteen percent of baseline before densification begins in earnest, and the diaphragm hypertrophies to keep tidal volume as the cage locks. The slowness is the safety mechanism. The waste minerals of the iron cascade are the feedstock. The folklore of the unbreakable body is a five-year deposition of the organism's own exhaust.