Around the time I and Naruto turned four, I started to be able to feel and control chakra, but I was a little confused because I could feel that most of my chakra was being pulled away before I could even use it by something unknown, leaving me with the same amount of chakra as a child though still above the average of most children. 

Since I was born I have been trying to shapeshift into something that is not me since I figured it would from birth but, ‘why did nothing ever happen?’

 But all the questions that had been bothering me since this new life started were finally answered when…one day after about a year of rotating my chakra.

 While rotating my chakra and teaching Naruto to do the same when I suddenly felt that the chakra wasn't being pulled away anymore and a huge amount of chakra gushed from me, but that was only the start because a few seconds later I felt a pain worse than anything I had ever felt before in both my mind and my body. 

“Kana!! What's happening.” Naruto said panicking while holding me.

 I started screaming in pain and clutching my shoulders till my fingers turned white and cold sweat running down my face and back.

Through the pain, It took me longer to control my chakra than it usually would but once I did and the pain that made me feel like my mind and body was remaking its self over and over again I noticed that the amount of chakra I had was even surpassing naruto and I could feel that something had changed about my body...

“Kana!!” 

‘It seems naruto had also felt my sudden increase in chakra but he couldn't figure out why I was in so much pain.’

After telling naruto that I am alright and will be meditating for a bit, he looked at me still very worried and then reluctantly went back to what he was doing.

After that I checked my body I found something different that I'm pretty sure is my shapeshifting ability but other than that I could still feel that there was still something more so I decided to go into my subconscious to find out what else changed.

Since the first time I went into my subconscious I had only come in here twice, both times Kurama's chakra was too overwhelming.

Once I was in my subconscious I looked around and started to walk to where I could feel Kurama's chakra. Soon I realized that the pressure I usually feel from Kurama wasn't making me scared like it used to. 

After walking only a few more steps before I could get to where Kurama was I saw a clean-looking white door that looked very out of place in this sewer-looking place.

After contemplating whether to go meet Kurama or to go through the door, I decided to open the door and see what's in here before meeting Kurama.

Once I walked through the door I saw what looked to be a library with the walls filled with books, a table in the middle of the room with a note placed on top of it, and one singular chair set beside it.

I walked up to the table and picked up the note that was placed on the table to read it. The note read

 ‘Dear Kana, 

You are probably are wondering why most of your chakra being pulled away, why you were never able to use your ability to shapeshift, and why didn't you get any of the fuinjutsu and adamantine chains you wished for. 

Well in order to answer that I will first have to apologize since I kinda-sorta forgot to explain everything that would need to be done to achieve the wishes you had made when we first met.

 Well back to the main topic, the reason why your chakra was being pulled away was that I needed a source of energy to make all the necessary changes to your body in order for me to be able to grant your wishes 

Since using chakra from your body is the most stable power source of energy that your body had access to and could handle I decided that this would be the best way to achieve your wishes. 

The pain you felt in your body was your body making the adjustments for the ability to shapeshift without using chakra and also to increase the rate at which you regenerate.

As for the pain in your head that was this room that I created in order to make sure that all the info about fuinjutsu and adamantine chains didn't kill you while I embedded it into your mind since the amount of information would overload your mind if you didn't have a place to store it.

Well, hope that answered all your questions.

Sincerely yours, God’

P.S.the info about using your shapeshifting ability is there in the bottom right of the bookshelf ;)

“Sigh...dumbass” 

‘I guess all these books are on fuinjutsu and the sealing chains.’ I thought while walking over to the books on my left and picking up the book that read basics on the spine.

 After opening the book I found that with every page I read it was as if every bit of information was absorbed and understood with ease, but after making it through about a book and a half I could feel that I got a bad headache when I tried to read the next page so decided to stop here for today. 

It seems that if I read more than my mind can handle I will get a headache.

After reading all the titles of all the books I found that it was all in order of what I would need to learn first to last, with the info on the basics of using the sealing chains around a quarter of the way in. 

“Sigh...well I have time to slowly learn anyway, let's take a look at the info on my shape shifting’

‘Hmm, I didn't get a headache?’ i thought questioning while reading the two books on my shapeshifting ability, why I didn't get a headache as I did, I guess that since the info was about something that my body will be able to do on instinct it wasn't too much info except the few things that I didn't know about my new body and some stuff to make it so I could use it more efficiently.

After finishing the book I decided I would go to meet Kurama.