The Third Raikag was the leader of Kumogakure a few decades before the start of the Fourth Shinobi World War. He was the father of A, the Fourth Raikage, and the adoptive father of Killer B.
The Third Raikage's reign was is best remembered for its constant attacks by the Eight-Tails, Gyuki, in Kumogakure. The Third on one occasion accidently wounded himself while collapsing with Gyuki from their even battle, an accidnt which became his life's shame due to his pride. After this, supported by his son, A, amoung others, the Third made it his personal duty to deal with Gyuki whenever its jinchuriki would lose control over it, being unwilling to ever destroy such a valuable weapon and always looking for suitable replacements to act as its new host. A task which, for a long time, was never accomplished. After his nephew lost control over Gyuki, the Third sealed it away in the Kohaku no Johei, resulting in his nephew dying. In between attacks from Gyuki, the Third would hold tests with his friend Dodai to try and find a tag-team partner for A, that being a tradition for the Raikage, with A being his future successor. Many times many, the children failed the test until fainally one managed to successfully perform the Double Lariat move with A. This student was later named "B", which eventually became Killer B. When B was five, the Third decided he would be the new jinchuriki of Gyuki, who was sealed within him. B became the first jinchuriki to be able to control Gyuki. In following years, the Third trained Darui, one of the most capable Jonin in the village currently, and passed on the secret of his Black Lightning to him. In later years, the Third faced an opposing force of ten-thousand men, which he held off for three days and nights by himself to allow his comrades to escape, albeit at the cost of his own life. Doing this caused him to become known far and wide for his extraordinary physical prowess.
The Third Raikage was revived, alongside his fellow Kage, Mu and the Second Mizukage, as well as the Fourth Kazekage as a military weapons for Akatsuki by Kabuto Yakushi. After Mu is detected by Gaara as he tries to approach the Fourth Division, Kabuto had him summon the others and the Third immediately questioned what was happening. Already knowing both Mu and the Second Mizukage, the Third seemingly recognized the Fourth Kazekage. During an argument between his two fellow Kage, the Third expressed his regret at not being able to fight all three like he wanted due to his bodily restraints by the Impure World Reincarnation. Being forced to pursue Gaara's Fourth Division by Kabuto, the Third, likewise to the others, expressed his disgust at having to fight with shinobi from his own village, but consoles the others with his belief that they have been surpassed by the future.
After they ad approached close enough, Gaara attacked them with his Quicksand Waterfall Flow technique, which his father countered, causing the Third to recognize him as the shinobi who controlled gold dust he knew in life, later praising him for having a powerful son when Gaara showed up. He was later restrained by Gaara's sand as he battle his father, which he later broke out of by use of his Lightning Release: Armor after Gaara sealed the Fourth Kazekage. Charging and smashing into the Fourth Division with the Second Mizukage, the two begin to relay their weaknesses to hasten their defeat. The Third telsl them hes a Lightning Release user and to put Earth Release users out front to build walls and have Wind Release for offense. During the division, headed at this point by Gaara's sister, Temari,'s struggle against him, their efforts against him proved ineffective, as his body only kept healing due to his being under the Impure World Reincarnation. Eventually, Naruto Uzumaki arrived to aide the division with a more powerful Wind Release technique, which the Third dodged twice in quick succession, before finally being struck by Naruto at close range. Though his Lightning Release: Armor had been deactivated prior to technique's effect, the Third's extraordinary physical durability completely protects him. He then begins to utilize his Hell Stab technique, which smashes through all the Earth Release walls thrown up to counter it easily.
Having already been taken over completely by Kabuto, the Third attacked Naruto, and his friend Dodai encased a substitution inside a rubber ball between them with Lava Release without the Third knowing and which he sent flying away. After breaking it open and realizing his error, the Third charged back after Naruto, who had contacted Gyuki, the Eight-Tails, for information on him. When he arrived he attempted to use his Hell Stab at full power against Naruto, he used Sage Mode to sense danger at the last possible moment and then struck the Third's elbow with his Rasengan, causing him to impale himself through the chest, which Naruto figured would happen. As his body started to crumble as a result of this, the division sealed him away. Later, after the release of the Impure World Reincarnation, his soul was returned to the afterlife, along with all the other revived shinobi besides Madara Uchiha. His soul was later summoned from the afterlife, along with many of the other previous Kage, by the Sage of Six Paths, Hagoromo Otsutsuki, to help the undead Hokage to teleport under his command into and back from his mother, Kaguya's dimension with team Seven and the dying Madara Uchiha. After Hashirama Senju and Madara have a brief talk before the latter dies, the third and the other previous Kage present, including the Hokage, are sent back into the afterlife by Hagoromo.
The Third Raikage was a very calm and serious individual, with a deep sense of honor and loyalty, shown in his reprimandment of Mu doe his underhandedness and in his sacrificing his own life to save his comrades when he died. He was a very proud man, having refused to discern the nature of the lightning-shaped scar on his chest due to his shame at it having been caused by his own technique. He also appeared to enjoy battle, as he told the other Kage that he would have loved to fight them all, and lamented on the shame that he couldn't. The Third was also very fearless, shown in the fact that he fought Gyuki, the Eight-Tails, all by himself and made it his personal duty.
As the Third Raikage, he was an immensely powerful and dangerous shinobi, considered to be the strongest Raikage in the history of Kumogakure. Perhaps the largest testament to his power was the fight that he, being the only one known to be able to do so, proved to be able to physically fight on even terms with a tailed beast like Gyuki, the Eight-Tails, who praised his power, saying he was very resilient and tough.
Like the other Raikage, the Third's primary fighting style, known as Nintaijutsu, was his use of his Lightning Release: Armor to enhance his physical strength and speed to extraordinary capability. His strength and durability was such that his body was called the strongest shield, evidenced when he managed to withstand Naruto Uzumaki's Rasenshuriken technique with little to no damage, despite the fact that his armor had been defused before he was hit, a feat which stunned Naruto. The only known technique strong enough to pierce his body was his own technique, the Hell Stab, which was similar to Kakashi Hatake's Lightning Blade and Sasuke Uchiha's Chidori techniques in that he focused his Lightning Release into his hand as a point. The Third could increase the technique's power by using less fingers. Using the Hell Stab, he once cut off all eight of Gyuki's tails, and was able to smash through enormous combined Earth Release techniques and take out dozens of allied shinobi immediately afterwards in one attack. His speed was so great that he was able to dodged the Rasenshuriken twice in rapid succession, which caused Naruto to remark that his speed was the same as his son, the Fourth Raikage. The Third also had mastery of a special type of Lightning Release technique known as Black Lightning, which he passed on to his student, Darui, who went on to become one of Kumogakure's greatest Jonin and later its Fifth Raikage. As a Lightning Release user, the Third's weakness was Wind Release, however, under the effect of the Summoning: Impure World Reincarnation technique, Wind Release proved ineffective against him as he was practically immortal. The Third also had enormous chakra reserves, able to use the Kohaku no Johei to seal the Eight-Tails and fight an army of 10,000 for three days and nights straight, which made him legendary.