Busou Renkin: Yokosu Papillion Park E

"Kazuki Muto is an average high school sophomore who plays the part of hero and pushes a girl from the striking blow of a slavering homunculus. In the process of saving the girl however, the monster plunges its tentacle through Kazuki's heart and kills him. Kazuto wakes up screaming and clutching his chest. His roommates in the dorm burst in and tell him to keep it down. Kazuki assumes that it was only a dream but he really died trying to save the girl who in turn resurrected him with the power of alchemy. The girl's name is Tokiko Tsumura and she affixed a Kakugane Medal on Kazuki's chest which was then absorbed into his body to grant him new life.

Along with his new heart and vitality, Kazuki is also gifted with a unique Busou Renkin (Arms Alchemy) weapon. In his case, Kazuki's Busou Renkin is a massive lance that's shaped like an arrowhead which can be used to destroy homunculus. In the animation, both the homunculus and Arms Alchemy were born from the practice of alchemy with the former being the artificial life created from techniques and the Arms being the product of weapons research and development. Tokiko's Arms are sort of like Doctor Octopus' arms except they're bladed and are called a Valkyrie Skirt. The homunculus feed on humans and the Arms are used to defeat them.