Kazuki Muto

Kazuki Muto (武藤カズキ Mutō Kazuki) is the main protagonist of Buso Renkin. He is an Alchemist Warrior with the Black Kakugane III (originally disguised as Kakugane LXX) implanted into his chest as a replacement heart and the older brother of Mahiro Muto. He is the main protagonist of the series.