Buso Renkin

Homunculi lurk among people in human guise, hunting the unsuspecting. Born from the experiments of European alchemists long ago, they’re notoriously hard to destroy—unless faced with Kurogane, specialized weapons that manifest according to their user’s instincts as unique powers known as Busou Renkin.

On his way home from school, Kazuki Muto tries to help a girl being attacked by one of these creatures, only for the encounter to upend everything he thought he knew. The girl, Tokiko Tsumura, reveals that she has inadvertently implanted a Kurogane within him, pulling Kazuki into a hidden war he never asked for. Forced to leave his ordinary days behind, he takes up the fight against the homunculi to protect those closest to him.