THE KEY: Naruto WILL Learn How to Recompose the Kyuubi's Yin and Yang Chakra
We have learned something called Yin and Yang chakra from Jiraiya and the Frog Scroll. So I went back a few chapters and i found that Yamato mentioned something similar. This makes me wonder, should Naruto focus on getting other elements or learn how to recompose the Kyuubi's chakra?
The thing is Naruto's chakra and the Kyuubi's are one so its almost impossible to draw out the chakra he was born with without some of the Kyuubi's chakra slipping out. So Naruto seems to have no choice, but to learn how to recompose the Kyuubi's Chakra.
THE KYUUBI'S YIN AND YANG: WHERE IS IT?
Both the Kyuubi's yin and yang are sealed within Naruto.
Here's the proof:
Jiraiya: "The very reason Minato went through the trouble of splitting the Kyuubi chakra into two... only sealing the yang chakra in Naruto was so that could leave it for Naruto"
So the yang chakra is also sealed but is sealed within Naruto's body. Both the Kyuubi's yin and yang is sealed within Naruto but was splitted up. His yin was sealed away behind the Shiki Fuujin seal while his yang was sealed within Naruto's body so that Naruto could use its power.
There's no arguement that Naruto is a jinchuruuki, but he's a special case. How the Kyuubi was sealed is complexed. It was so complex that even a Key to the seal was made and left. Kyuubi yang chakra is mixing or more so merge with Naruto's chakra. Jiraiya's first comments of the seal told us that its was meant to do this.
The seal keeping Kyuubi's yin chakra back is slowly weakening. Meaning that Naruto is slowly gaining all the Kyuubi chakra yin and yang. The yang is the dominant chakra and is the one mixed with Naruto's. The weakening seal is allowing the yin, who Kyuubi is in control of, mix with the yang chakra already in Naruto.
THE MISCONCEPTION ABOUT THE KYUUBI'S YIN AND THE SHIKI FUUJIN
You might be saying Naruto does not have both the Kyuubi's yin and yang. Some believe the yin is inside the Death God's belly.
The caster of the Shiki Fuujin has various options. A caster could seal a target in the Death God's belly OR place the seal on a container and seal the target behind the Shiki Fuujin seal. Some believe all targets sealed with Shiki Fuujin goes inside the Death God's belly. That is a misconception. Naruto is a special case because Minato used a complex sealing technique which splitted the Kyuubi's chakra into yin and yang, sealing the yang inside Naruto and sealing the yin behind the Shiki Fuujin seal WHICH IS ALSO IN NARUTO'S BODY.
See what happens when the caster has the Death God seal the target into yourself:
Sarutobi does demonstrate what Shiki Fuujin does do, but people keep on forgetting that Sarutobi planned on taking the Shodai, Nidaime, and Orochimaru with him while Minato planned on entrusting the Kyuubi to Naruto from the very beginning to make his son a jinchuuruki. THAT IS THE DIFFERENCE.
MINATO'S SHIKI FUUJIN: A COMPLEX SEALING TECHNIQUE
Naruto's case is very unusual because this type of sealing is very complex, and Naruto is the only person in the entire world who has ever undergone the process.
Bijuus are nothing more than massive formations of chakra. BIJUUS HAVE NO PHYSICAL FORM, UNLIKE HUMANS WHO HAS BOTH BODY (PHYSICAL) AND SOUL (SPIRITUAL). But still since the Kyuubi is just a massive form of chakra, THIS CHAKRA CONSISTS OF YIN AND YANG.
Now, we haven't had an explanation on how yin and yang works yet, so as of right now, I'm going to make a very reasonable case. Yin = Spiritual energy, and Yang = physical energy (read an old thread here for more info). A bijuu's "soul" is its yin chakra, and its "body" would be its yang chakra.
Naruto has two seals on him: Shiki Fuujin and Hakke no Fuujin-Shiki. Shiki Fuujin only sealed the yin, and what was left Hakke no Fuujin-Shiki was used to seal the yang into Naruto's own body. There are only 2 plausible locations for where the Kyuubi's yin chakra is housed:
1. The stomach of the Death God.
2. The Shiki Fuujin seal itself.
One doesn't make sense because Naruto has Shiki Fuujin on him (Sarutobi had the Shiki Fuujin seal on his body plus he intended to seal the souls of Nidaime and Shodaime INSIDE THE DEATH GOD'S BELLY, but Minato did not intend to seal the Kyuubi inside the Death God's belly, he sealed it INSIDE NARUTO), so which leaves the second option. Two makes sense if you consider Tsunade's regeneration seal used for her trump card, which seals/stores her chakra INSIDE THE SEAL ON HER FOREHEAD, similar to the yin chakra sealed INSIDE THE SHIKI FUUJIN SEAL.
To put it simply, Minato sealed the Kyuubi's yin and it is locked away within the Shiki Fuujin seal itself. Afterwards, he proceeded to seal the Kyuubi's yang chakra into Naruto's own body with Hakke no Fuujin-Shiki.
NARUTO HARNESSING THE KYUUBI'S FULL POWER: CONTROL OF YIN AND YANG
I just cant see how Naruto can take on someone like Pein, including his 7 Bijuus with a new rasengan or more clones. Only someone like Shodai or Minato can accomplish something of that caliber.
Naruto is light years away from that kind of power, but there is a short cut and that is the Kyuubi. ( He doesnt have time to wait the world depends on it).
Its not that I dont believe Naruto can't develop the skill to take on Pein and his 7 or 8 Bijuu, its just that there is no human who can fight a supposed God and seven Bijuus at the same time without some sort of divine intervention (Kyuubi) lol.
The form he took against Kakuzu is the only time Naruto was in complete control over the Kyuubi chakra. There was no sign of visual chakra, and no sinister or evil feeling emitting from him. The only sign that he was using Kyuubi charka was his eye went Kyuubi. Hell Naruto's personality even stayed the same. He wasnt berserk like he normally gets when he goes Kyuubi.
This is why Jiraiya focused mainly on controlling the Kyuubi's chakra in Naruto's 2 and a half-year training instead of other skills. This shows that Jiriaya knew what he was doing and i believe Yamato and Kakashi will discover this later on. It's time they realize that Naruto's chakra and the Kyuubi's are one and no matter what the Kyuubi's chakra will always sip out when Naruto attempts to draw his own out.
The Kyuubi is Naruto's power. Lets be realistic here. Naruto's chakra is the only chakra that can withstand the corrosive nature of the Kyuubi's chakra (kinda like YIN & YANG). I repeat THE ONLY chakra that can do that.
That itself should mean that Naruto is the only one meant to control that horrible power and put it to good use.
Minato wouldn't have put the Kyuubi in his own son if he knew it was something that wasn't beneficial ( it was his son. His only son for crying out loud). Minato wanted Naruto to make the Kyuubi his power.
He wanted it to be a tool just like the way a sharingan is considered a tool. That's why entrusting that kind of power to his son was worth dying for.