Sora

Sora is a monk in the Naruto Series. His name means "sky" in Japanese. Sora also has the Nine-Tailed Demon Fox's chakra which was enhanced in him genetically which he has one arm of a jinchuriki. Sora wants revenge on Asuma for killing his father.

Background
Not much is known about his childhood, only that one day he went berserk and wrecked the Temple of Fire, a place otherwise believed to be an indestructable fortress. Afterwards, he was loathed by some of the monks of the temple, and soon began receiving the same treatment as a Jinchūriki.

He wanted to become part of the Twelve Ninja Guardians. He hates himself because of his powers and gets angry when people stare at him. When they first meet he hates Naruto but then they become friends. Sora does not like getting help from people, especially ninja. He did not even want Team Yamato to come.

Fire Temple Filler Arc
This arc begins due to a misunderstanding, Naruto Uzumaki fights one of the monks-in-training from the Fire Temple, Sora, who uses also wind chakra based techniques. After the confusion, the monks and Team Kakashi travel to the Fire Temple

The temple monks explain that the tombs hold the loyal bodyguards of Fire Country's feudal lord. Naruto observes Sora sparring with other monks and becomes offended upon realizing he is holding back. Naruto challenges Sora, but just as the matter is about to get serious, another monk stops him. Naruto realizes Sora is despised by the other monks as he was himself and wishes to befriend him. Naruto visits Sora again and observes him practicing his wind jutsu in earnest, hoping to get strong enough to avenge his father. They later return to the temple to receive news that another tomb has been robbed.

They are later ambushed by a group of enemy shinobi and Sora, unwilling to look for Naruto, goes off on his own. Sora then hits upon the enemy leader, Furido, and it is revealed that he was the group's target. He then starts to question Furido but Furido does not answer them. Instead he just sits down and roast some potatoes. Sora gets angry and his chakra starts to get get more powerful. Furido taunts Sora until Sora unleashes his true powers, before informing Sora that he is planning to use the four corpses to save the Land of Fire. After an explosion Sora wakes up only to find out that Furido had vanished, only leaving him a clue that he knows his father and that Sora resembles him.

Sora then is assigned to go to Konohagakure with Team Yamato to replace Sai because of Sai's injuries.

Naruto tries to show Sora around Konoha but Sora goes his own way. Sora's insults precipitate a brawl with Kiba Inuzuka and Choji Akimichi, and Naruto and Rock Lee soon join in. Later Asuma Sarutobi tells Sora he knew Sora's father, who is revealed as one of the Guardians involved in the coup attempt. He also shows Sora his chakra blade attack and then volunteers to to help train Sora and Naruto.

Asuma supervises Naruto and Sora's wind chakra training, and notices that Sora, like Naruto, has very powerful chakra. Later, Asuma gives Sora a claw made from the same materials as his chakra blades. It is revealed that Asuma killed Sora's father Kazuma, who had planned to kill the Hokage. Furido then approaches Sora, telling him that Asuma is responsible for his father's death and passing him two "king" pieces from a Shogi set for Asuma. Shocked by this discovery he goes back to training distressed. Then Naruto approaches a furious Sora in the training grounds, who easily throws a chakra-powered kunai through a tree and destroys the stone behind it.

Later on Sora tries to look for Asuma and follows him to Danzo's interrogation. There he found out that Homura Mitokado and Koharu Utatane dislikes Sora and doesn't welcome him in the village and plans to kill him. Before Tsunade can make her decision on what to do with Sora, he is caught by ANBU members in the ceiling. Enraged he yells at Tsunade asking her why would she kill him is his powers really that hated. He then goes on by saying that they are just like the fire temple monks. He looks at Yamato asking him is this what you call comrades. He then change is view towards Asuma and confronts Asuma, accusing him of killing his father, which Asuma confirms. Sora attacks Asuma, his arm once again assuming a demonic form. While he blows Asuma outside, he is unable to maintain it for long, and falters. He is attacked by an unknown individual (presumed to be a Root shinobi), but Naruto shields him from the shurikens, being injured in the process. Sora then approaches Furido, who says that he must kill Asuma and Tsunade to avenge his father and consolidate the "two kings" (the Feudal Lord and the Hokage) into a single leader by eliminating the Hokage.

Later that night Naruto catches Sora going after Tsunade. Sora retreats as Shizune and a few other ninja arrive, and Naruto pursues him. At that moment, a mysterious lightning storm strikes, cutting off power to the entire village. Meanwhile, Naruto chases Sora for attempting to kill Tsunade. Asuma, commanded by Tsunade to follow Sora and Naruto, finally catches up to them. Asuma realizes that the four invaders plan to annihilate the entire village using the lightning powers of the corpses that they stole. The revelation shocks Sora. As Asuma leaves to help hold off the attackers, he instructs Naruto to continue to pursue Sora.

Later on Furido tells Sora that when The Nine Tailed Fox rampaged around Konoha, The Fourth Hokage sealed the beast with in Naruto Uzumaki and the nine tails chakra that had slipped out when it rampaged was sealed it into Sora by Kazuma and the fire temple. He, Furido, then proceeds to use the Five Elements Unseal to release all of the demon fox's power. Sora grows a demon fox cloak similar to Naruto's except that he has three spikes on each side of his face.

Like Naruto, he grows a tail which increases in number the longer he keeps himself in the demon fox cloak state. If the nine tails grow, he will turn into a real demon fox. Later as Asuma and Naruto arrive it is revealed that Furido is actually Kazuma, Sora's father.

Abilities
Sora is a wind natured chakra user like Naruto. He is able to manipulate wind into chakra infused wind blades of energy capable of cutting through most material including rock. He wields a tri-bladed death claw that he learns to infuse with chakra after learning the jutsu from Asuma Sarutobi. Asuma gives him a new blade after his old one is destroyed in a fight with Naruto. Sora also uses Taijutsu known only to the monks of the Fire Temple.
 * Element: Wind

Sora's father Kazuma spliced his cellular make-up with excess chakra of the Nine-Tailed Demon Fox to create a pseudo-jinchūriki. Sora is capable, though unwillingly it seems, to transform into a miniature kyūbi much like Naruto. In this form, he has all the power and resistance to injury and attack of an unsealed kyūbi.

Trivia

 * Sora is introduced as a "filler" character in Naruto: Shippūden, and thus doesn't make an appearance in the manga.