By simply tapping into the demon fox's chakra, Ryun's blue eyes turn red, his pupils become slitted, his nails and canine teeth grow long and sharp, his brown hair becomes longer and spikier, and his whisker marks become more feral. Depending on how much chakra is unleashed, the blackish-red chakra could glow around his body in an untamed way. Ryun first reached this form when Tora Uchiha's friends tried to separate him from Ryun, causing the pure rage to take over allowing the demon fox's chakra to leak out of the seal.
Even though this is the weakest state of his Jinchūriki forms, it is still a deadly foe as it increases his physical strength and healing well above most shinobi, and increases his speed to such high levels that nothing short of a fully matured Sharingan is able to track his movements. Until special training from Madara Uchiha, Ryun could only reach this state through rage or if his life was in imminent danger, but after having a inner talk with the demon fox, he is able to tap into the demon fox's chakra on his own, or by simply telling the demon fox to give him some power.
During Ryun's battle with Jake at a ravine on the Land of Fire's border, when Ryun was at the mercy of Jake, the demon fox told Ryun that he should be grateful to it and gave him more chakra. The amount of chakra is so great that it leaks out of his body in a denser state. All the physical traits of the basic Jinchūriki form are present and slightly altered, including a black ring appearing around his eyes, longer nails and canines, and more berserk looking eyes, with one major bonus; the red chakra becomes a complete shield around his body, in the shape of a fox, complete with long ears and a tail, known as the demon fox's cloak or shroud.
In his one-tailed transformation, Ryun fights more like a beast. Instead of using his fists, he uses his sharpened claws.In this form Ryun has also shown the ability like in his other forms to make a shockwave with a simple wave of an arm. While he can stand on his own two feet, he can move at greater speeds on all fours. But his most powerful weapon is the chakra itself. The bubbling chakra appears to have a mind of its own: when a strike that was meant for Jake missed, the chakra itself stretched off Ryun's arm and hit Jake before he could react. Since the chakra has a mind of its own, it is extremely difficult, if not impossible, to predict Ryun's movements, as Jake was able to see Ryun perfectly, but couldn't predict what the chakra would do with the Rin'negan. The chakra can stretch far from the body, as Ryun was shown using his "arms" to attack Jake from great distances, at one point being on an opposite side of the valley, and still attacking him with the chakra arms. The shield around his body appears to be impenetrable, comparable to Gaara's Ultimate Absolute Defense: Shield of Shukaku.
After catching the Kagekenin member, Kaci Wells, and beating what he thought was Kaci to pieces only Ryun to slip into his two-tailed transformation. His physical characteristics match the first two forms, but his red eyes and canines grow larger, and his lips get a black outline, similar to fox gums. The chakra shield's only difference between the one-tailed transformation and the two-tailed is the extra chakra tail that has grown.
While in this state, Ryun is still in control of his body, though to what extent is unknown. He once punched a tree, destroying it and a long line of trees behind it, and later he attempted to attack Sanji of the Black Sea, who later tried to calm him down, and possibly tried to stop him from finding Kaci. The amount of chakra produced by the two-tailed transformation was so great, that even Seireitou Hyuga doubled over in pain from the chakra.
After Javelin Sanmaru revealed himself to S.W.O.R.D. and baited Ryun with news of Tora, Ryun went on a rage and first attacked him in his one-tailed state. When that failed, along with further baiting from Javelin, Ryun skipped the two-tailed transformation altogether, and went straight into his three-tailed transformation. The three-tailed state looks similar to the two-tailed state with the demon fox's features on Ryun becoming more pronounced. Also, another difference includes the number of tails. His eyes later become similar to the four-tailed transformation, but can return to normal.
The amount of chakra produced from this form is devastating. The very air around Ryun begins to hurt. This is the strongest form Ryun can reach and control. With the standard chakra shield's protection and attack power, a simple roar has the power to create a devastating sphere of destruction.
When Javelin further taunted Ryun about Tora, Ryun in a fit of fury and anger, slipped into the demon fox's grasp. The demon fox's chakra began to burn its way through Ryun's body, destroying his skin, and rapidly healing it at the same time, eventually covering his entire body in a mix between the demon fox's chakra and his own blood. Everything from his face to his chakra tails became completely solid, his eyes losing its characteristics and becoming empty glowing circles surrounded by a black mask made of chakra.
In this state, in effect, Ryun takes the place of the demon fox inside the cage. The demon fox has complete control over Ryun's body, making it a mere skeleton for the fox's chakra, and every living thing in its way a target. The four-tailed transformation has all the benefits of the other tails, with upgrades. With a simple wave of his hand, it can send a shock wave of destruction for miles. The chakra shield, while being solid, still completely protects Ryun's body, and is so hot that it can burn the skin on contact. If Naruto is hit, the chakra itself can form another body, and strike back almost instantly. The demon fox also has the ability to charge a concentrated ball of chakra, consume it, and then fire it with such a force that it could destroy five Rashomon gates without losing strength. Finally its chakra shield's defensive power is so great that it is impregnable to any form of attack. Even Seireitou's legendary KyuubiTaishou couldn't break the exterior shell of the demon fox's chakra, only bending it slightly.
In the end, despite it being one of Ryun's strongest Jinchūriki forms revealed so far, the four-tailed transformation is Ryun's greatest downfall. Because the demon fox's chakra is constantly destroying and creating new cells, it also shortens Ryun's life, similar to Tsunade's Creation Rebirth. Also, because the demon fox has complete control, Naruto will attack anything that moves, including his friends. This discourages Ryun from using this state more than the fact that it shortens his life.
Releasing even more chakra than before, even from his mouth, and growing a sixth chakra tail, Ryun's skin finishes peeling off and in an instant explosion of chakra he is completely covered in the demon fox cloak, resembling a miniature demon fox. With Ryun, the demon fox's cloak takes on a black, orange color.
Also, Ryun'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.
He possesses the same powers as in his Four-Tailed Transformation, but his attacks, like the Four-Tailed Fox Kokuho, seems to be significantly stronger. He is still more powerful than most ninjas and could easily overpower Seireitou even when he was using his Shukai (although it could be debated that Seireitou wasn't actually trying to fight against Ryun, so how much more powerful he really was is still unknown).
While transformed Ryun is completely covered by the chakra of his Tailed Beast. In this form, his chakra takes the form of a Ten Tails, shaped by a fiery blackish red chakra, with no pupils in her eyes.
Ryun maintains a high level of control over this Jinchūriki form. With chakra emanating from out of him, he will hunch over and the Fox demon itself will materialize. Smaller than the similar Shukaku form, the Ten-Tails still proves a threat. In this form Ryun is able to emit fiery spectral Kokuhos from the fox's mouth. These blasts are very destructive and when coupled with the Ten-Tails strength, the surrounding area can be reduced to rubble. However there is speculation of to what degree of control he has.
During his fight with Naruto, Ryun allowed the chakra to completely consume him. While his facial features still remain slightly human, both his eyes resemble the Ten Tail's with the same markings around its body.
In this form, Ryun is able to use Kokuho with apparent great ease as most of his body is now chakra. He can use the Ten Tail's Rin'negan. In addition much like Naruto's chakra shield, the chakra is capable of absorbing a wide variety of attacks.
When Ryun was in a rage after a fight with Seireitou Hyuga, he slowly slipped into his Nine Tailed form. In this form the chakra on his back slowly breaks down and becomes black fur, which begins to cover his body, covering his arms and then his face distorting it and giving it the Fox's features such as the red eye and slits, and he grows a ninth tail.
In this form, his speed and jumps have increased. He can use the chakra on his arms to stretch his limbs to extraordinary lengths. This form allows him to even fire off his limbs at will, but still have them remain under his control, as he was able to pin Seireitou to a tree and then slowly crush him as his battle continued.
Technically this isn't a Jinchūriki form as its a transformation into the Fox itself. After being hit by Seireitou's Kokuho and moments away from being hit by a second, Ryun in desperation, instantly created a giant copy of Ten Tails with himself hidden inside.
When Ryun needs the Fox's full power, he allows the Fox to take full control over his body. While taking over the body, it's eyes will become more apparent, changing from a simple light red pupil, to its original version of a red pupil with a small black slit in it.
Jinchūriki Chakra Control
In the event of the demon fox manifesting, Ryun's cousin, Tora, gave Ryun a special written seal that is to be placed on his body. This seal suppresses the demon fox's chakra and restores Ryun to his normal self. In addition, Sanji has demonstrated a technique that reverses Ryun's demon fox transformation, enhanced greatly by the Ryun's own care for his cousins. Ryun has shown that with enough will power, he is able to suppress the demon fox's chakra from taking over. However, the important factor to this is that the demon fox's chakra was responding to the vessel of its residual chakra so it is unknown if Ryun could use his willpower to suppress the demon fox's chakra if it forced its way in a similar fashion as his first four-tailed transformation. Sasuke has also demonstrated the ability to forcefully suppress the demon fox's chakra.
The fox has an unnaturally large supply of chakra that Ryun can use. It's presence inside Ryun allows him to manipulate chakra at will. As a added bonus for Ryun, it can move the chakra on its own to protect Ryun from any harm it can in order to preserve its own life. It should be noted however, unlike Naruto's constant battle for control over his body with the demon fox, Ryun is technically never subjugated to this.