Six Paths Mode

The Six Paths Mode is a unique form taken by those who can use the Six Paths Senjutsu in tandem with their tailed beast chakra. It seems to require the user posses a Rinnegan as well.

Overview
A rare transformation, first used by Hagoromo Ōtsutsuki, and an advanced form of the Six Paths Senjutsu, the user splits their chakra from the normal two parts—physical and spiritual energies—into five; physical, spiritual, natural, and tailed beast. When used together with the Rinnegan, the user gains this form.

Drawbacks
This unique mode carries the same negation to natural energy as the Truth-Seeking Balls, and thus, senjutsu as a whole. Because of this, only sages stand a real chance of fighting on even ground with the technique user, or have any hopes of damaging the technique user, while in this state.

Hagoromo's Version
Little is known about Hagoromo's variation, save that he was the first to use the form.

Ryun's Version
Ryun Uchiha, as the jinchūriki of Myōbu—who is essentially a clone of Kurama, the Nine-Tails—has access to the beast's gargantuan reserves of chakra and can tap on it to access transformations into part or all of the beast. Having been sealed within him at birth, the beast and Ryun grew alongside one another, and while on friendly grounds personally, at first, Ryun couldn't control Myōbu's power due to the lingering hatred of Kurama's which remained in the fox's chakra.

Overtime, however, Myōbu regained yang chakra, which it could infuse with its own will, allowing him to control part of its power. Later, after his training with Hikaru Kurosaki, Ryun was able to remove the Nine-Tails' influence from Myōbu's chakra, allowing him to use the full capabilities of the beast as one of the few jinchūriki capable of doing so without losing full control. Unique to most jinchūriki, as the two literally grew up alongside one another, their chakra is also unique, in that it has, over the decades, become one; making it easier for the two to aid each other in combat.

This mode largely has many physical similarities to the Truth-Seeking Balls; the Yin-Yang tailed beast chakra encapsulates the user's body, forming a shell that is unable to be broken by ninjutsu. Though not visible, due to the appearance of the user's eyes while in this state, the Rinnegan remains active the duration of this form's use, making the user also immune from genjutsu. The user's speed and strength are highly invigorated, though neither skill is rarely used, substituted for the use of the black chakra spheres. They are, however, vulnerable to taijutsu.

According to Fujoshi Shihōin, the user is also able to ignore all barrier ninjutsu, as the sphere's simply rotate around them, devouring any form of chakra it touches, making barriers useless impediments before the user's path. The incredible life energy present in the yang chakra, which is part of the technique, also allows the user to rapidly heal any would-be injury they could receive.

Early on in Ryun's appearances within the series, Myōbu allowed him to transform full into the fox itself. However, because he could only control the fox's smaller yang chakra (due to the yin chakra being infested with Kurama's hatred), his was incomplete; only allowing for a chakra shroud which replicated the size and power of the actual beast. Despite this, the replica proved to be immensely powerful, giving Ryun access to the Tailed Beast Ball, which he often used liberally against Seireitou Hyūga. His most common method of attack was to use the beast's ability to generate shockwaves with a simple roar to buffet his opponents.

In the human version of his Tailed Beast Mode, Ryun's chakra shroud changes from its original form. An entire uniform, complete with a white haori and a dark-colored hakama, constructed entirely from chakra, enshrouds his body. The kosode itself is decorated with nine magatama, corresponding to the fact that Myōbu is a piece of Kurama's chakra, and therefore, is a representation of Kurama's nine tails. In this humanoid form, Ryun can partially transform into Myōbu and make use of a smaller version of the Tailed Beast Ball. The shroud itself still retains the basic functions of the original Chakra Mode.

After gaining a piece of the ' chakra, Ryun's transformation becomes even closer to that of the Sage of the Six Paths. His long hair is dyed a brilliant shade of white and his chakra cloak becomes a robe with monkey fur lining the edges.