Doctor Butterfly is the leader of LXE. His original name was Bakushaku Chouno  and he is the still-living great-great grandfather of Koshaku Chouno (Papillon). Dr. Butterfly has a moth-shaped mustache, and his battle outfit resembles a white version of Papillon&#039;s, with an attached a cape. He considers Papillon weak, saying he cannot go very far on his own, which leads Papillon to challenge him to a fight with their Buso Renkin.

The story begins when high school student Kazuki Muto is killed one night saving a mysterious girl from a monster, only to wake up in his school dorm, believing it to have been a dream. However, he soon finds out that dream wasn't a dream at all when a giant serpentine monster attacks him and his sister. Tokiko Tsumura, the girl he saved, explains that the monster is a homunculus. Kazuki had been attacked and killed by it when he was rescuing her. However, she, feeling responsible for him, revived him by placing a Kakugane medallion in his chest, serving as a replacement heart.<br><br>
The Kakugane, as Tokiko explains, is an alchemical device that, when activated, takes a certain form based on the Kakugane's user, forming a unique Buso Renkin. The Buso Renkin is the only thing that can destroy a homunculus monster. Using this, Kazuki creates his own Buso Renkin (the "Sunlight Heart", a huge lance). Along with Tokiko and her own Buso Renkin (the "Valkyrie Skirt", an execution scythe), Kazuki joins the fight against the homunculi and their master.

"He has recently left Viz Media due to low pay, and Kenpachi was subsequently recast."

Hometown: Gunma prefecture, Japan  
Height:176 cm  
Weight: 76 kg

Buso Renkin is the story of teenager Kazuki Muto, who dies trying to save a girl who was being attacked by an eerie monster. The next morning, however, Kazuki is left wondering whether it was all a dream. Lo and behold, the girl, the monster, and his death are all real! The girl, Tokiko Tsumura, was actually trying to slay the homunculus (a beast that can take the form of humans, but whose main source of food is people), but Kazuki got in her way. To revive Kazuki, Tokiko replaces his heart with a "kakugane," an alchemic device that allows him to summon a lance with which to fight the monsters. It turns out that Tokiko is a member of Renkin Kenshi (Alchemist Soldiers), an organization sworn to protect the world from the diabolical creatures. Soon, Kazuki joins Tokiko in her quest to terminate the sinister being that creates and controls the homunculus.
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(Source: Viz Media)