Amatsu looks at Mito and asks "Granny Mito did I do it right?" with an innocent look on his face. He knows for a fact he did it perfectly but he had to act like he didn't know.
Mito looks at the genius little boy and spoke "My dear, you did it perfectly. In all my years I have never seen or heard of someone ever learning fuinjutsu or anything this easily before." She hesitated before continuing on. She knows that most future shinobi preferred to learn cool and fancy ninjutsu, but it would be terrible to pass up this opportunity to pass on all of her fuinjutsu knowledge.
"Amatsu dear, I would like to officially train you in fuinjutsu. I will be honest I only have a few years left and I would like to pass on everything I know onto you." explained Mito.
Amatsu looked at Mito with a shocked expression. Not because she has only a few years left, since he has read the manga, but because she wants to teach him everything. And he is only 1 years old. It is crazy. But he is not gonna say no, that would be stupid.
"Well, I hope you live a long life Granny, but of course I would like to learn fuinjutsu from you!" Spoke Amatsu excitedly. This made Mito smile. She was happy that he was so enthusiastic about learning and she loved this little boys smile. She had to do what needed to be done to protect this smile, even if it means using rather crude methods.
"So, let us begin your training!" spoke Mito as she began to talk about the next seals. She would explain their uses and then demonstrate how to do them. After which she would have Amatsu make the seals as well. She was not as surprised as when he had first completed the exploding tag seal, but was still shocked with just how quickly he was picking up on these.
As the day progresses into the late afternoon, she had taught him all the seals up to B-rank. At first she was only going to teach him some D-rank, but the kid just kept on succeeding and with no signs of chakra depletion either.
"This boy is very interesting, Mito." spoke a dark and gravely voice inside Mito's head. "As I know you are planning to seal me into that girl, but it might be more interesting to be sealed inside him. HAHAHA"
"Now, now, Kurama. While that might be true and he is a very interesting boy. We do not know if he would be able to handle your chakra, where as Kushina we know for sure can." Mito said telepathically to Kurama.
Mito looked at Amatsu and spoke "Well my dear, let us call it a day and start preparing a dinner for when Kushina comes home from the academy."
"Ok Granny!" Amatsu said excitedly as he began to clean up his fuinjutsu tools. He decided to quickly make a storage scroll, by drawing the seals for the enclosing technique on a scroll. He then then stored the materials inside. He then scurried off to the kitchen to help prepare dinner.
A couple of hours later Kushina and another person arrives. Kushina speaks "Granny Mito, Little Matsu!!! I am home from academy!!!"
Amatsu came running from the kitchen and jumped into Kushina, clinging to her like a koala. "Big Sis Kushina! I missed you today! And Guess what I learned!!!" He was speaking quickly and loudly, as expected of the little brother of the red-hot habanero.
Kushina hugged him back and thought to herself 'My little Matsu is soooo cute! I just can not get enough of his hugs!' She had a huge smile on her face.
The person behind her just sighed. She was a blonde girl, standing about 5 foot 4 inches, with a very nice body shape. When Amatsu looked at her, he was excited since she was always a favorite character of his in his previous life, Tsunade.
"What is it Big Sis Tsunade? I bet your just jealous since I get to hug this little guy everyday" teased Kushina.
"No I just can not believe how ridiculous you are being right now" said Tsunade with slightly blushing cheeks. 'There is no way I will let you know how jealous it makes me!' she thought to herself.
Amatsu just looked at the two of them and then said "I got to learn fuinjutsu today! Granny Mito taught me a lot!" he said this with a proud smile on his face. He brings out his scroll and suddenly the brush, ink, and several papers tags.
He threw the tags into the air, then in one motion dipped the brush in the ink and sent the chakra through the brush. In a moment he made five exploding tags. He caught the tags and stored his materials into his scroll again. He gave both Kushina and Tsunade the tags.
When they saw him quickly draw the seals they were impressed, but assumed it just looked good with no actual chakra in it. But once they held the tags they could tell it was created perfectly. What surprised Tsunade the most was that the chakra control was so perfect that she could not even tell that he was using the chakra. As a ninja she is able to sense whenever someone is using chakra near her, especially this close, but this time she did not sense a thing.
"Amatsu, Kushina, and Tsunade, please come to eat while the food is hot" said Mito from the other room.
Amatsu rushed off to the dinning room with Kushina and Tsunade in tow. As everyone took their seats around the table, they saw a delicious looking dish filled with hotpot. As the evening went on Kushina talked about her day at the academy and Amatsu talked about his day learning fuinjutsu.
After dinner the kids went to bed leaving just Mito and Tsunade together.
Tsunade spoke first "How was he able to learn seal for the exploding tags in a single day? And to top it off so efficiently?" Her voice was clearly that of someone in shock.
Mito laughed gently, while shaking her head.
"What so funny? He is only 1 years old and his proficiency is higher than what most shinobi could ever achieve." Tsunade said with a slight tone of irritation.
"My dear Tsuna, I was not laughing about that. I was laughing at the fact that you think that is all he learned today. Today I taught him every fuinjutsu I knew and have access to up to B-rank. I plan to teach him everything and at this rate it will probably take a month at most for him to learn and master everything." said Mito with a proud look on her face. While his is her adopted grandson and not her blood grandson, she was as proud as could be from his talent, progress, and eagerness.
Tsunade had a blank expression. And how could she not, she has been learning fuinjutsu for years and is nowhere near mastering everything Grandma Mito knows. But she thinks a little boy of one, can learn everything in a single month. If that is true he needs to be protected.
As if she knew what Tsunade was thinking and was going to say Mito spoke up "I plan to speak to Hiruzen. I will make it clear on the exact standing of Amatsu. He is my final disciple, grandson, and will be the heir to the Uzumaki Clan. I will make it very clear that should anything happen to him while I am alive or after there will be hell to pay. There is someone else who has taken a liking to him as well and he is way more unforgiving than I am." The last part made her chuckle as she said it. She knows full well how Kurama would handle anyone that went against him.
Tsunade looked at Mito's serious face and could only sigh. She felt bad for her teacher, but she agreed with Mito completely. After they finished speaking, Tsunade left for the night and Mito went to bed.