Hiraga Gengai 平賀 源外 is Edo's Number 1 inventor. Both he and his son Hiraga Saburou 平賀 三郎 loved tinkering with machines and robots. Father and son came into conflict because son was against his father's attitude towards machines, and thereafter left home to join Kiheitai 鬼兵隊. Unfortunately, as a result of his involvement with this extremist group, son was beheaded by the Bakufu government.
Hiraga Gengai's philosophy is that 「男のからくりは鎧・大砲・キャタピラ」 'The machines of men are Armour, Big Canons, "Caterpillars" '.