Doctor Butterfly (ドクター・バタフライ, Dokutā Batafurai) is the leader of LXE. His original name was Bakushaku Chono (蝶野 爆爵, Chōno Bakushaku?) and he is the still-living great-great grandfather of Koshaku Chōno (Papillon). Dr. Butterfly has a moth-shaped mustache, and his battle outfit resembles a white version of Papillon'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.

He uses Kakugane LXX, the real version of the Kakugane that Kazuki supposedly owns, which manifests as the Buso Renkin Alice in Wonderland (アリス・イン・ワンダーランド, Arisu in Wandārando?). This Chaff Buso Renkin has the same wing-like structure as Papillon's Near Death Happiness, but is platinum-white and confuses the nervous system. In concentrated mode, it is also able to directly affect a person's brain, giving the person hallucinations and illusions. Alice in Wonderland is also capable of disrupting radio and electric waves, and when in contact with water, can create a mist.

(Sources: Wikipedia, MAL User Icy_Auron)