Kazuma

, also known as, was a member of the Twelve Guardian Ninja, and eventually led half of the group to stage a coup d'etat against the Hokage. He was also the father of Sora, as well as the main antagonist of the anime-only Fire Temple arc.

Background
Kazuma was once part of the Twelve Guardian Ninja. He later tried to persuade the daimyo into "uniting" the country by ridding it of the Hokage, as he felt that the Land of Fire only needed one "king". However, he was stopped by Asuma Sarutobi, who told him that the daimyo did not agree with him. After a long fight, Kazuma, Asuma, and Chiriku were left as the only surviving members of the Twelve Guardian Ninja. Kazuma then had one final showdown with Asuma, where he was ultimately struck down. Chiriku was the only one who knew about this, and kept it a secret.

Despite Asuma and Chiriku's initial belief, Kazuma had survived. His goals had not changed despite all his allies now being dead. He spent the next several years training and working on a new plan. By the time he felt ready to carry out his plan, his appearance had changed so much that Asuma barely recognized him. He later changed his name to Furido and persuaded Fuen, Fūka, and Fudō to join him in his plan to rid the Land of Fire of one of its "kings". During the Fire Temple filler arc, he was seen with a long pale scar going diagonally across his face. It can be assumed that he received this scar from the finishing strike of Asuma.

During the attack of the Nine-Tailed Demon Fox on Konoha, Kazuma discovered that the Nine-Tails' chakra was so great that it had leaked out. Kazuma took advantage of this by collecting the extra chakra. He then infused Sora with this chakra and cells from the Nine-Tails, and kept it mostly contained inside his son with various seals as insurance for later.

Personality
According to Sora, Kazuma was once a kind, loyal, and upbeat man who took pride in his appearance and abilities, which was proven by how hard he trained and how diligent he was in keeping his Twelve Guardian Ninja sash clean and in good condition. According to Asuma, Kazuma was a man with great faith in his beliefs, and was willing to put it all on the line for his dreams to come true. During the Fire Temple filler arc, Kazuma proved to have much resolve in the actions he took. Despite his status as the villain, he truly believed that his goal for "uniting" the Land of Fire by getting rid of Konohagakure was the right thing to do.

As Furido, he appeared to be laid-back and a little goofy, regularly making light of the battle. But this only served to distract others from his true nature. In truth, Kazuma would stop at nothing to "unite" the Land of Fire. He had abandoned all forms of emotional attachment to pursue his goals, regardless of who he must sacrifice, as he showed through his use of his own son.

Abilities
Kazuma demonstrated great taijutsu prowess, as shown from his ability to toy with Sora in battle, who is highly skilled in close-range combat. His primary weapon in battle was a multi-section Monk Staff, where the top could be split in multiple parts with a chain in between the joints, and could destroy rocks and trees in the blink of an eye. It was strong enough to block Asuma's wind-enhanced trench knives. He was also seen wielding a triple-bladed claw that he could infuse with wind chakra.

Kazuma also showed impressive knowledge of sealing jutsu, demonstrated from how easily he and his team passed through Fuen's giant seal and how effectively he kept Sora's demon chakra contained until he finally chose to release it. His knowledge was also great enough to dispel techniques used on him, like Sai's ink jutsu binding him. He could also revive the dead, which he demonstrated using two different methods. The first version required a large area of earth, which would allow him to continuously summon people as mindless zombies. The second version would bring a person back as a perfect reincarnation, but required a large amount of energy (i.e. electricity). It would seem that he was also able to use his earth element to camouflage himself in a forest environment.

Twelve Guardian Ninja Arc
Kazuma encountered Team Yamato in the fields near the Fire Temple, after they had been lured there by the stolen bodies of Kitane, Tōu, Seito and Nauma. There, he came face-to-face with Sora again for the first time in years. Clearly, Kazuma was more interested in how Sora used his powers than how he had grown as a person. During their skirmish, Kazuma continued to taunt Sora to force him to show more of his true power. Eventually, Kazuma performed the Five Elements Unseal on Sora, causing his son's demonic arm to appear more frequently.

Later, shortly before the attack on Konoha, he revealed to Sora that it had been Asuma who had "killed" his father as part of his plan to get Sora to join him. Initially he had convinced Sora to join him in his plans to destroy Konoha's "king", but then Sora had discovered that Kazuma intended to also destroy the entire village and all of its inhabitants, prompting Sora to help stop him. When his initial plan to destroy Konoha by using four resurrected Ninja Guardian members to perform Limelight failed, he decided to rely on unleashing the full force of Sora's demonic chakra, knowing full well that Sora's body would not be able to handle it and that he would ultimately destroy everything around him.

After all of Kazuma's allies perished, Asuma and Team Yamato caught up to Kazuma, where Asuma revealed who Kazuma really was. It was then that Kazuma revealed that it was because of him that Sora possessed his demonic powers. Whilst Naruto tried to deal with Sora, Asuma chased after Kazuma into the woods. There Asuma scolded Kazuma for using Sora as a tool and weapon. Eventually, Kazuma was captured (with assistance from Sai). Asuma tried one last time to make Kazuma understand that his goal was unnecessary as, in reality, they were both trying to protect the wrong king. Refusing to believe that, Kazuma broke free and attempted to finish off Asuma, but was struck down by his former ally. As Kazuma died, he voiced his fear for the future of the country. Asuma merely stated that it would continue to exist as it always has because of Konoha, which Kazuma scoffed at.

Trivia

 * As an anime filler character, Kazuma seemed to be made as an extension over the repeated talking about the "true king" during the Hidan and Kakuzu Arc.
 * Kazuma's favorite food seemed to be roasted sweet potatoes, which he was seen eating often.
 * While for different reasons, Kazuma and Minato Namikaze both put part of the Nine-Tailed Demon Fox into their respective son.