The supernatural alloy produced by gathering the essence of alchemy is the Kakugane. This device activates upon a person's fighting instinct, manifesting the possessor's inner power into a tangible form, creating a weapon like no other. Its name: Buso Renkin.
This will be a story happening approx. 100 years before the manga and anime. There's been a war for the past decade between the Alchemist Warriors and the Homunculi. Which side are you on?