Dodai

He is an instructor in Kumogakure.

Background
In A's flashback, he was seen telling a group of children that only one of them would earn the name "B" and become the tag-team partner of A. He then instructed them on how to perform the Double Lariat on the training dummy. As the prospective candidates failed one after the other, he lamented that the day seemed as though it would end in failure until he sees A and a young Killer B decapitate the dummy.

Appearance
Along with the standard outfit of the Kumogakure shinobi including the one-strap-over flak jacket, he wore an eye patch over his left eye and a stylised forehead protector in the form of a hat.