A is the son of the Third Raikage, who groomed him for the position of the Fourth Raikage. At some point in the past, due to A not having a blood sibling who could be his tag-partner, try-outs consisting of young children were gathered in order to determine one, in keeping with a long-standing Kumogakure tradition of the Raikage having a tag-team partner. After many attempts, they found only one child who was able to successfully match A’s power and use the Lightning Release: Double Lariat on a training dummy.

As a result, that child was given the name “B”, and A stated that they would be brothers from that day on. He and B would eventually be teamed together on a mission with A’s cousin, the jinchūriki of the Eight-Tails. While on the mission, he told A that Killer B would need something to fill the void that would be created if he was chosen as the beast’s next jinchūriki.