Jirōbō

was the physically strongest member of the Sound Four but the weakest overall, according to the other members of the Sound Four.

Personality
He disliked it when Tayuya used foul language or when she called him "fatso", and complained to her about it. Despite this, he proceeded to call Chōji Akimichi fat near-constantly during their battle. At first Jirōbō appeared as the silent yet slightly irritated member of the group; until the Sasuke Retrieval Arc in which he revealed an overly sarcastic and arrogant persona. Like several other Sound Four, however, he had his own perception of morality, criticising Shikamaru for what he saw as giving up on Chōji and selling his teammates out, which led to his demise at the hands of an overly-enraged Chōji. Jirōbō tends to get hungry at all times, and stays behind to feed, which leads to him slowing down the team. Like the rest of the Sound Five, Jirōbō constantly referred to his enemies as "trash". He wasn't however above showing his idea of pity towards them as shown in his battle against Chōji.

Abilities
Jirōbō could drain chakra. He was almost always hungry, and he could get the same energy from absorbing opponents' chakra that one would get from food.

Like the rest of the Sound Four, he had a cursed seal. When in cursed seal level 2 form, his skin became red, his Mohawk became a mane down his back, and he gained ten times his normal strength. Also, by working together, they are skilled in barrier and sealing ninjutsu. 

Arhat Fist
Jirōbō had great physical strength, such that, when in his cursed seal level 2 form, he could lift a mountain-sized Chōji. Much of his strength is refined into the Arhat Fist fighting style, which combined simple taijutsu strikes with Jirōbō's incredible physical strength to cause massive damage to his opponents. Using this he could manipulate the earth with his strength from creating barriers to lifting massive sheets of rock. Jirōbō was the physically strongest of the Sound Four but the weakest overall according to the other members.

Earth Release
Jirōbō specialised in Earth Release techniques to compliment his physical prowess, such as throwing large chunks of earth or forming a defensive earth wall. He can also form a prison of earth to drain his opponent's chakra.

Konoha Invasion Arc
Jirōbō made his first appearance with the rest of the Sound Four, erecting a barrier to keep others from interfering in Orochimaru's fight with the Third Hokage. He and the rest of the Sound Four later escorted Orochimaru when he fled.

Sasuke Retrieval Arc
The Sound Four escorts Sasuke Uchiha when he decides to join sides with Orochimaru. After the Sasuke Retrieval Team found the Sound Four, they were all caught in Shikamaru's shadow. Sakon's brother, Ukon, then attacked him from cover and broke his hold on the rest. Jirōbō then allowed the rest of his group to go ahead of him while he used Earth Release Barrier: Earth Prison Dome of Magnificent Nothingness to trap the retrieval team and started to drain their chakra. Using his Byakugan, Neji Hyūga discovered this and alerted the rest of his team.

Kiba Inuzuka and Akamaru then attempted to break through the wall, but their attempts to escape were ineffective as the wall rebuilt itself, and their attacks became weaker as Jirōbō slowly absorbed more and more of their chakra. Team leader Shikamaru Nara offered to give up on Sasuke and sacrifice the other members of his team if Jirōbō would let him go, but Jirōbō refused, explaining that Shikamaru deserved to die for those actions. Shikamaru had no real interest in forfeiting, and only spoke to Jirōbō to confirm his location. The team focused their attacks on the area of the dome furthest from Jirōbō - and thus the weakest - and were able to escape.

Naruto Uzumaki and Kiba then attacked Jirōbō, but he easily repelled them. The retrieval team then went into hiding, but Jirōbō easily discovered their location and, after using a very powerful Earth Release technique, caught Shikamaru. He then tried to kill him saying to the rest of the team they didn't want to follow a guy like him. Chōji Akimichi managed to save Shikamaru just in time however. Jirōbō then expressed his sympathies that they had a leader as "useless" as Shikamaru and offered to kill them quickly so they wouldn't realise how unfortunate they were. His words prompted Chōji Akimichi to demand he face Jirōbō 1-on-1. He gave Shikamaru some supplies,saying he had his secret weapon with him. Jirōbō mocked this and charged saying he would finish them. Chōji then took one of his clan's Three Coloured Pills, giving him the strength he needed to match Jirōbō. He caught Jirōbō by his belt, much to his surprise, and sent the rest of the team away with his promise that he would defeat Jirōbō. Jirōbō told Chōji once he had killed him, his friends would be next. Chōji then stated that might not be as easy as he thought it was, overpowered him, and threw him against a tree.

When Chōji continued to counter his attacks, Jirōbō activated level one of his cursed seal to overpower Chōji. He then started to pound him while stating that Chōji was left behind because he was the weakest member of the team, sacrificed for the others' benefit. Chōji did not believe that and took a second pill, which gave him significant chakra which he used to expand his arm and leg and repel Jirōbō. Jirōbō then caught him and threw him into the air. Chōji then became a giant and attempted to crush Jirōbō.

Jirōbō then advanced his cursed seal to its second stage, giving him enough strength to lift the giant Chōji and knock him in the air. Chōji reverted to his normal size, fell to the ground, and was unable to move. Jirōbō then drained the last of his chakra saying he would need it now that he was in the second stage of his cursed seal. When he was not satisfied, Jirōbō threw him on the ground,causing a bag of potato chips amongst Chōji's belongings to fall out, which he ate the last one of before repeating what he had said before: that Chōji was fat, that he was the weakest member of the team, and that he had no friends. He moved to finish off Chōji, but Chōji took the last of his Three Coloured Pills, which converted all his fat reserves into chakra, and dodged him. Jirōbō then tried to attack Chōji, but he easily overpowered him as he was now a hundred times as strong as before. Chōji then struck Jirōbō down, saying he could forgive the insults, or even that Jirōbō had eaten the last of his favourite snack, but that he would obliterate him for what he had said about Shikamaru. Chōji then channelled all of his chakra into his left fist to prepare the Butterfly Bullet Bombing technique and told Jirōbō that attack was worth his whole life. Jirōbō begged Chōji to stop, but Chōji punched him in the chest for eating the last chip and insulting Shikamaru, creating a giant crater and at the same time crushed Jirōbō's heart, killing him instantly. Jirōbō's body then reverted to its original appearance and he laid defeated in the bottom of the crater, leaving Chōji the victor of their battle.

Trivia

 * Jirōbō can be seen during the Konoha Sports festival and the omake of Naruto Shippūden episode 129.