Arms Alchemy follows Hero and Ordinary High School Student Kazuki Muto as he journeys into
the world of Alchemists and their Renkin as they fight the Homunculi. No, not the Fullmetal Alchemist ones, though there is definite overlap between the series theme wise. The series is in many ways a parody of the shonen genre and hence often has tongue planted firmly in cheek.
Kazuki Muto, a typical student, once saved a girl pursued by a monster. As a result, Kazuki takes the hit and killed ... but woke up he realizes that it was only a dream. But not long lasted Kazuki calm, he again meets the monster, and realizes that his death was real. Then again there rescued the girl and the hero explains that the monster - a homunculus created by alchemy. Among other things, in the chest Kazuki Muto is no beating heart, and Kokugan - an alchemical device, the best weapon against the homunculi.