Sora's Jinchūriki Forms

When the Nine-Tailed Demon Fox attacked Konohagakure, it left a lot of chakra in the surrounding areas, which was later gathered by Kazuma, one of the Twelve Guardian Ninja, who wanted to create a Jinchūriki weapon for the fire country to use against Konoha. After five years of experimentation, he finally was able to implant the demon fox's chakra into the cells of his son, Sora. Because Sora does not have the Tailed Beast sealed within him, but only has his cells combined with its chakra, he is refered to as a Pseudo-Jinchūriki (Pseudo: from Greek ψευδής "lying, false").

Even though Sora does not have the actual demon fox inside of him, the chakra implanted within him can react to the demon fox within Naruto Uzumaki as it somehow called out to him when Naruto was about to be killed by Fuka. Unlike Naruto, he doesn't have as much chakra as the demon fox would usually generate when Naruto is in his demon fox cloak, nor can he control it. Instead, he becomes overwhelmed by the fox chakra's destructive instinct; when in his fox cloak, Sora threatens to kill anyone who stands in his way.

Jinchūriki Form
Unlike Naruto, who has a stable and controlled combination of his own chakra and the Nine-Tailed Demon Fox's chakra (because of the Fourth Hokage's seal), Sora can't control the chakra added to his cells. To stabilize this, his father applied a sealing jutsu on Sora several times to keep him and the chakra under control.

When Sora feels frustrated or is in a state of great anger, the chakra can change his right arm into a demonic form. It would seem that he is not aware at all about the change of his arm, and has first noticed it when his father told him. In this form the demon fox's chakra does not control Sora's body fully.

One-Tailed Transformation
When his father would stop applying the seals or when he completely releases it, he uses the Five Elements Unseal, which the chakra can run loose and slowly take over Sora's body.

Like Naruto, when the chakra is released from Sora in large amounts, a demon fox cloak will form around Sora, initially and slowly he will begin to grow a chakra tail. In addition, like with Naruto, during this transformation, Sora's hair becomes spiked, his canines longer and sharper, and his eyes turned to slitted fox-like eyes. Also in this form, the chakra surrounding him damages the people around him. In addition, he is also able to inflict a painful burn to anyone that comes into contact with the chakra for too long.

Due to being a Pseudo-Jinchūriki, Sora has some different features from Naruto in a similar state (besides the arm) including spiked projections growing from his cheeks.

At first when the chakra was taking over his body and he was in pain, and could slightly control himself, but slowly he began giving in to the urges of the demon fox's chakra, and gains a will to kill and destroy everything, a problem Naruto never displayed until the fourth tail emerged.

Three-Tailed Transformation
Because Sora got angrier and angrier, he skipped the two-tailed form and grew the third chakra tail. Like Naruto, he begins crouching on all fours. However, unlike Naruto, he has now given in to the demon fox chakra completely, and will only growl and roar, something Naruto never really displayed during his Three-Tailed Transformation, where he seems to still be in slight control.

Like Naruto has in this form, Sora will also gain the ability to blow his opponent away using a simple roar of chakra, and has also displayed the ability to use the extended chakra arm.

Four-Tailed Transformation
Releasing even more chakra than before, even from his mouth, and growing a fourth chakra tail, Sora's skin begins to slowly peel off and in an instant explosion of chakra he is completely covered in the demon fox cloak, resembling a miniature demon fox. With Sora, the demon fox's cloak takes on a yellow, orange color, while Naruto's cloak is more red.

Also, Sora's legs are thinner and longer, and the spikes sprouting from his face in his earlier transformations is visible in the cloak, alongside his spiked hair, being slightly bigger than when Naruto transformed. In this form, he has absolutely no control of himself.

The Main difference in Naruto's and Sora's transformations, are why the Demon Fox's chakra makes them transform. Naruto's chakra melts away his skin so as the Demon Foxes mass(Bones, Muscles, Ect.) can form over him, pushing him further into a completed transformation, whereas Sora can never fully turn Kyuubi (the Demon's main spirit is based in Naruto, NOT Sora)and his skin only burns due to the intensity and nature of the foxes chakra, because of this, Sora retains more of his skin (His feral facial markings remain visibal even in his highest transformation level),

He possesses the same powers like Naruto in his Four-Tailed Transformation, but his attacks, like the Four-Tailed Fox Menacing Ball, seems to be significantly weaker than Naruto's (Sora's Four-Tailed Fox Menacing Ball could only destroy a small part of a forest). Yamato speculates that this is because Sora's body is too frail to keep up with the incredible chakra the four-tailed form gives him. Nevertheless, he is still more powerful than most ninjas and could easily overpower Naruto even when he was using his Three-tailed form. However, Naruto was trying to talk through to Sora in an attempt to reach out to him and talk him out of giving himself into the chakra, instead of physically fight him, so how much more powerful is still unknown (and will most likely never be known).