Nine-Tails Chakra Mode

Nine-Tails Chakra Mode is a heightened transformation unique to those with the Nine-Tails' chakra sealed into them. Naruto Uzumaki, as the Nine-Tails' jinchūriki, is able to enter the form using the beast's Yang chakra. Minato Namikaze, having sealed the beast's Yin chakra into his body immediately before his death, has been able to access the form once reincarnated.

Appearance
While the mode is active, Naruto gains a chakra shroud with six magatama around his neck and two distinctive pieces of hair-like horns resembling the Sage of the Six Paths' silhouette along with a swirl design that resembles the Uzumaki clan's symbol. The colour of his eyes changes from blue to orange when he is in this form and while the demon fox shroud is red and releases chakra as acidic bubbles, this form's shroud is yellow and releases chakra as flickering flames. After forming a friendship with Kurama, Naruto later gains the additional seals that appear on his hands while in Tailed Beast Mode. While in this form Naruto's chakra signature and smell are different as noted by Neji and Kiba.

When used by Minato, it holds resemblance to something in between both of Naruto's similar forms; while predominately looking like Naruto's, Minato's shroud also does have the additional seals that are similar to the ones on Naruto's hands and feet, and additional magatama design that appears on his collar while in Tailed Beast Mode. The bangs at the sides of Minato's face go upwards in this mode as well. There are subtle differences between their designs of the seals spread over their cloaks.

Attributes
As with all jinchūriki transformations, the Nine-Tails Chakra Mode gives the user increased strength, speed, and defences. Nine-Tails Chakra Mode's increases are noticeably superior: Naruto becomes strong enough to push a fully formed Tailed Beast Ball through a multiple layered barrier with just one arm, neutralise White Zetsu with a single kick despite their durability, and, in collaboration with B in his full Eight-Tails form, he could also knock down Tobi's Demonic Statue of the Outer Path with an uppercut. Naruto's speed is so great in this form that Killer B even had trouble determining if he had used the Body Flicker Technique when attacking Kisame, he could even surpass the speed of a fully charged A, as well as blitz the extremely fast Third Raikage before the shinobi had any chance to react. Naruto's durability is also very high in this form that he was able to endure extreme heat with only a slight burn.

Naruto is able to use chakra arms while in Nine-Tails Chakra Mode. Like other jinchūriki he can use the arms to improve his dexterity and manoeuvrability, granting him increased means of interacting with his environment and his opponents. More unique to Naruto, he uses the arms as substitutes for shadow clones in his creation of various Rasengan-variants. Instead of needing a shadow clone to help him with shape transformation, he can do both with just one hand, either his own or the hands of his chakra arms. He still needs more than one hand for the nature transformation of the Rasenshuriken, but this also is accomplished without shadow clones. Once the Rasengan-variants are formed, Naruto can then use the chakra arms to deliver them across long distances or, in the case of Rasenshuriken, guide them to their target. Initially, Naruto tried to create a technique related to the Tailed Beast Ball: the Tailed Beast Rasengan. However, he later develops a more effective version of this technique: the Super Mini-Tailed Beast Ball, which is basically a miniature Tailed Beast Ball that he's able to control with the help of a shadow clone.

Like his predecessor, Mito Uzumaki, Naruto gains Kurama's ability to sense negative emotions, something that not even the best sensor-type ninja can do. In addition, he is capable of sensing Kurama's chakra signature, even while he was inside a chakra isolation chamber within the Falls of Truth; as well as the ability to sense other chakra signatures from great distances. Due to having Kurama's Yang chakra in this form, Wood Release techniques will react to the chakra's life-giving properties and mature into full-grown trees within a matter of seconds, either by contact or close range.

Using Nine-Tails Chakra Mode was initially a risk as Naruto had to temporarily "shelve" his own chakra in order to use Kurama's, which allowed the fox to automatically drain Naruto's. If Kurama managed to take all of Naruto's chakra, Naruto would die. Shadow clones provided an additional risk, as Kurama would absorb every portion of Naruto's chakra even faster for each clone he made. Moreover, Naruto also had to be careful about the amount of time he spent in this mode as there was a limit to how much chakra Naruto managed to pull away from Kurama. Despite these risks, once involving himself in the Fourth Shinobi World War, Naruto deployed several shadow clones while he was in this mode and even managed to remain in the form for an entire night. The Eight-Tails says this is because at some point Kurama had purposely stopped taking Naruto's chakra. After Naruto forms a friendship with Kurama these handicaps no longer apply.

Tailed Beast Mode
All jinchūriki can enter Tailed Beast Mode, which grants them all the strength and abilities of their corresponding tailed beast. But where other jinchūriki become full-scale replicas of their tailed beast, Naruto (initially) enters a form very visually similar to his Nine-Tails Chakra Mode. The shroud parts down the middle and opens up into a full-length cloak (haori), revealing a black undergarment with three magatama on each side of his high collar. His seal's numerous swirl-patterns, which were located all over his body, open out into complete, dark, circles. His eyes become red and slitted and his whisker-markings become much thicker, as they do in his early transformations.

Naruto's speed and strength are once more increased in this form, to the point that he was able to deflect five Tailed Beast Balls by simply moving past them. His ability to create different Rasengan without the use of shadow clones remains. Additionally, he can transfer the Nine-Tails's chakra to others, granting them version 1 chakra shrouds that, among other advantages, dramatically improve the strength of their techniques; Kakashi Hatake estimated that his Kamui was at least three times more powerful than usual. Naruto can remotely control each individual shroud, such as forming tails for his allies to deflect incoming projectiles. Despite the Nine-Tails' contributions, the chakra produced more closely resembles Naruto's than just Kurama's as noted by C.

Naruto is able to become a full-scale replica of Kurama, but he is not "in the flesh" so to speak. Rather, the modified Nine-Tails Chakra Mode enlarges into a tailed beast-cloak that recreates Kurama's overall form, while retaining the exact same seal that was previously present on Naruto's body. As opposed to the normal nature of the chakra, it no longer burns those who touch it. It is also translucent, as Naruto can be seen inside the replica's head for the duration of the transformation. Appearance aside, Naruto gains the usual advantages of Tailed Beast Mode, notably the ability to perform Tailed Beast Balls. He can even use the tails of this form as arms to interact with other large targets. Uniquely to Naruto, he can still perform his usual techniques while in this form, such as making shadow clones.

Naruto cannot maintain Tailed Beast Mode indefinitely because he and Kurama have not yet formed a perfect bond. They are improving: at first they could only last for five minutes, but by the time of the Ten-Tails' revival they extend it to eight minutes.

Trivia

 * When first observing Naruto's enhanced chakra shroud while in Tailed Beast Mode from behind, Kakashi Hatake momentarily mistook Naruto for Minato.
 * In the Chikara Arc, despite the fact that Naruto had not yet subjugated the Nine-Tails' power, motivated by the Tonika Village orphans' plea to save Dokku and Shiseru, Naruto temporarily assumed an incomplete version of the Nine-Tails Chakra Mode after breaking free from Kurama's influence. During his brief time in the form, Naruto was able to form an incomplete Tailed Beast Rasengan as well. He was also able to enter an imperfect version of the Tailed Beast Mode, in which his seal spread over his body, forming unique markings. Much like Tailed Beast Mode, Naruto's chakra manifested into a replica of Kurama, although it lacked legs and possessed only six tails. In addition to the shroud's tails, Naruto was capable of forming chakra arms to bind his opponents while in this state.