Distorted

In this post apocalyptic nation, a failed mass nuclear bombing around the world interlaced with chemical reaction to our strongest gene, Prion, leaves 3/4 of the population destroyed, yet for them to come back faster, stronger, and obtain a hunger for humans. Bones and all.
Their skeletons are now metallic, giving them abilities beyond belief. Each one differs ability wise. Some stronger and weaker. The entire world is torn apart.
The only hope is a controlled environment turned into an academy for students to "learn" about the gene. In reality, the school is an introduction to a damned bloodbath they will soon face, otherwise known as "assessments."
All of this is in control of a headmaster who to the remaining population on Earth is honored, but should be scalded for the secrets hiding behind her name and her school.