The not-so-bright Iwanbou is not what you think. People view the large guy as nothing but a complete idiot. Looks can be deceiving. Really, Iwanbou is not an actual person. Inside of his belly is his controller, the puppet master that goes by the name of Gein.

There are three versions of Iwanbou. The first was the one who joined the Juppon Gatana, but later disappeared after the battle at the Aoiya. This version was simply used just to dig up some information on Kenshin before Enishi would carry out his revenge upon the rurouni. The second version was created to conceal a bomb that would later badly damage the Dojo Maekawa. Sanosuke kept it as a souvenir, but later dumped it after noticing that it started to decay. And the third and final version of Iwanbou was the most dangerous of all. It was composed of shock absorbers, a free-jointed device, steel control wires, and of course, the main ingredient for all versions if Iwanbou, human flesh. Gein created this Iwanbou specifically for fighting purposes and tested it against Kenshin himself, but it was destroyed by the Amakakeru Ryuu no Hirameki.