Former 4th Seat Officer of the Seventh Division. He is the younger Brother of Jidanbō Ikkanzaka. He was known as the "Kamaitachi," which means the greatest airborne weapon or Wind-scythe.

Jirōbō is a very boastful man, talking the entire time during his fight with Ishida simply about how they should give up since he is the greatest projectile expert and so on. He is also very cowardly. Jirōbō attempted to kill Orihime while she did not notice, and upon realizing the difference of power between Ishida and himself, attempted once again to either injure or capture her. This placed him at odds with the chivalrous Quincy, resulting in the loss of his abilities.