Monster

Neurosurgeon Kenzou Tenma has a brilliant future at a prestigious German hospital until he refuses an order to abandon a wounded child in favor of treating an influential patient who arrived later. He saves the boy, Johan Liebert, and pays for the decision with his career prospects and engagement. Soon afterward, several hospital officials die mysteriously, and Johan disappears with his sister.

Years later, Tenma learns the horrifying truth: the child he saved has become a killer with an extraordinary ability to manipulate people. Convinced that his own hands returned a "monster" to the world, Tenma abandons his old life to pursue Johan across Europe, entering a trail of murders, buried memories, and experiments that shaped the boy he once chose to save.