Iwanbou  

The Round Demon, 夷腕坊

In essence, Iwanbou is an obese oaf who utilizes his immense size, strength, and ability to trap weapons within his flabby frame. Despite being extremely dimwitted, he participated in the Battle of Aoiya and displayed a foolish grin throughout the encounter. Following this event, Iwanbou was last seen on a cliff outside Kyoto. It has been revealed through the Jinchūuu or "Revenge" arc of the manga that Iwanbou is actually a mechanical puppet controlled by Gein, a primitive mech with significant influence in Enishi's revenge plot.