Ok first things first I'm gonna go in to more detail in the next chapter and second Kyuubi and Naruto have worked to fix the seal that was fucking up his chakra control and reserves, strength, and intelligence but with the nearly endless knowledge of Kybuui helping him he quickly learned to fix the seal. All of this was done at a very young age. SO GET OFF MY BACK YOU ASSHOLES!

P.S this is only for the flamers!