I do not own Naruto in any format, this is a fan fiction.
The next morning Naruto and Arturia had a rather nice breakfast and he began to learn the principals of magic. Merlin told him than at first he wanted for him to learn from books he was going to let him read, he told him they were old, and he needed to be gentle with them, they were his personal library after all. He sure was happy that Kyuubi taught him the shadow clone jitsu, it looks like it would take years to finish reading all these books otherwise.
As soon as Merlin went out of the room where he had shown his library to Naruto he heard a noise, a rather strange noise, but he figured it was Naruto picking the first book to read. This gave him enough time to get his other gear ready for training. Rayudo was not known to like his students to be unprepared for training, he right down hated slackers. Naruto made a dozen shadow clones and manage to read the first bookcase in the room. He had to remember to dispelled the clones one at a time or he was going to feel dizzy again. The other thing was that the more he read the more books would appear.
It was getting close to the afternoon, and Merlin decided to check on his students progress. "Naruto you need to read the books in that bookcase first. Only then will you understand the book you are holding." Naruto told him he finished that bookcase and half of the one the book he was holding came from, he was simply reviewing the last book he finished. Merlin of course did not believe him and asked him 10 questions from the books he said he finished by picking random books and asking a question. Naruto of course answered every question correctly.
"But how did you do it?" Merlin wanted to know this method of speed reading. Naruto made the necessary hand signs and made three shadow clones. "What ever they learn, I learn when I dispell them. Kyuubi taught it to me last night." Merlin asked who was this Kyuubi, and Naruto was told that an introduction was needed to tell him to place his hand on his stomach and think of following him.
Merlin did just that and he entered into Naturo's mindscape. He saw a big fox with nine tails behind him, his fur looked like it was made of fire. "So you are the one that talked to Rayudo. The demon fox that guards this boy?" Kyuubi told him no father would let his son be harmed if he could help it, he told him his name was Kurama, but Naruto called him Kyuubi from his title. He told the old man his complete title. "Why did you teach him that technique?" To help his son train more efficiently was the only answer.
Merlin understood what the intentions of the fox were, he truly loved Naruto as if he was his son. Arturia and Rayudo came in the house soon after and told him to grab his gear and to follow him outside. At first Naruto was a little upset that this guy didn't even greet him properly. 'Would it kill him to say good morning?'
The first lesson was how to put on armor, it was made thanks to Merlin's magic, the armor will change size and weight as he got bigger and stronger. The whole thing felt like he was carrying a ton of rocks strapped to his entire body. Rayudo then told him to follow his example and do as he did. After he finished showing the exercise he told him to repeat it a hundred times, before they would continue to the next. It was hours later and he finished the entire exercise routine. Naruto felt like he was hurting in places that he didn't know could hurt as much.
"Well now I should probably tell you, to rest cause tomorrow we start weight training in the same armor you are wearing? Questions?" Naruto only had a couple, when was he actually going to learn to fight? And last but not least is training going to be an never ending torture session? The answer to the first was when he could move in that armor with little to no effort, second answer was no, it is not torture, it simply the way to condition him to have be able to withstand a massive amount of pain. Demons don't exactly know the meaning of the word mercy.
"So get some dinner, take a bath and I will see you tomorrow." He felt like he was going to crawl to his home. Merlin was laughing his head off when he saw Naruto. The poor guy was dragging his feet. Arturia on the other hand was mad, "It's your first day of training, I been doing that since I could walk, don't tell me a little warmup and you are out for the count, talk about a major weakling." Naruto was not going to argue he wanted a bath and tomgo to sleep, to hell with the idea of having dinner. He was in such pain, he could probably not swallow.
"Sorry that I disappointed you, your majesty." He asked Merlin if he could get out of the armor and change into something he could move easier in. Merlin being the kind man that he was summoned a change of clothes for him. First came of the helm, and he dropped it on the ground. The helm hit the ground so hard it made a small hole. Then the chest plate, Arturia quit making fun after he saw his chest. Bruised, broken bones, and dark stains of what looked like dried blood.
He put his shirt on and threw the chest plate, creating another hole in the group. Lastly his leggings, same as the chest plate, but his underpants were soaking with sweat. He threw that next to the chest plate and finally his gauntlets fingers bruised and he threw them on the ground too. He told Merlin he would come and pick it up after his bath, and went inside his house. The old man tried to pick his helm up, but couldn't. He tried using his magic and he barely got it off the ground.
"What is wrong with the armor, I made it so that he it would get heavier as he got stronger. There is something clearly wrong. That is when he saw it, someone had drawn a seal to absorve his magic power, the effect that happened was that the armor became heavier by several times than it should. "Now why would anyone do something like this, it clear that the person did not want the seal found. He broke the seal and the piece of armor becane light again.
"Now who would do something like this.." Arturia was trying to sneak in their home without making a sound. "So it was you Arturia, why would you do something so reckless? It could have killed him." Arturia looked at him with an angry look on her face, "Don't care, why does he get to train with you and my instructor. It is not fair that he has magic and I don't." Merlin knew what this was Hus adopted daughter was feeling envious that he had magic power and was being trained by him, and she did not.
"Arturia, you too will have magic power but your magic core is still immature, just as you are for pulling such a dangerous prank. If Naruto did not have the help of that other being, he could have died wearing this much weight. Arturia simply called him a wimp. "So you think he is a wimp. Very well you do not need to apologize to him, if you can pick up one if his gauntlets. But if you can't you will apologize young lady." She began to mumble how heavy could they be.
She tried and tried and tried some more. The stupid gauntlet must be stuck. She told Merlin that there was no way he wore that, he must have used a spell to make it even heavier than what she expected, "He one day could, only thing is he doesn't know how to cast spells yet, he knows only theory." This made Arturia realize what she had done, if Naruto was an ordinary person this could have killed him. She decided to tell him that she was sorry.
Naruto was soaking his wounds when he suddenly fell asleep, and was standing once again in front of the Kyuubi. "Wait don't tell me I over did it again, right?" Kyuubi told him that was not the case this time, he told him something was taking energy from him and made the armor heavier and heavier as time went on. "So somebody trying to kill us?" Kyuubi told him that if it was someone trying to do that, they either did not do the trap right, or they were amateurs.
"But thanks to this happening has forced me to teach you the next skill that I was going to teach you later, due to this trap now your body can withstand it." Kyuubi made a design appear on a stone tablet. "This us a seal that will do what they tried to do, but this we control how many times heavier you are. It's called a gravity seal, increases the effects of gravity on your entire body." Naruto studied the design and was confident he could draw it.
"Now where is Naruto, he is taking to long for just a bath." When Arturua saw him unconscious on the floor she screamed for Merlin, who came running to see what was the matter. "I was afraid of this, come on Arturia look the other way so I can get him dressed, and take him to his bed, he must have been more exhausted than what he let on." Arturia was berating herself for doing something as foolish, just because he could use magic before she even knew that eventually son would she.
Naruto woke up bright and early and under the supervision of Kyuubi, he drew the seal right over where his heart should be. He activated it and went to the kitchen. Arturia was first to tell him that she was the one that made his armor so heavy, and that she was sorry. Naruto greeted them both and got a cup of tea and looked what Merlin made for breakfast. "Sorry about what? I have to admit that was one hell of a prank. Completely caught me off guard. So if anything it just reminded me I should watch my surroundings and be more careful, you never know when someone or something might try to kill me."
To her this felt horrible, if he trusted her before, she felt that due to this prank, he might never trust her again. Merlin was smiling and told him he was right, that which does not kill, can only make him stronger. "By the way how long are you planing to wear that seal?" Naruto saw the look in Merlin's eyes, he could see it. "Probably till I retire or expire which ever comes first."
He helped served each their breakfast and after eating and washing his dishes, he went to thr library to begin reading. Arturia was still troubled by how he had responded to her apology. What she saw left her speechless, there were no less than 12 copies of Naruto each reading a different book, while one was meditating. "Arturia, I am a little busy, make it quick I don't have much time to spare."
Each word made her feel as if someone punched her heart. "I am truly sorry, I was envious if you being able to use magic when I couldn't I wanted you to be on an equal footing with me and I was wrong, turns out I too will be able to cast spells, only later than you." Naruto did not say a word, he kept doing what he had been doing.
A fiery energy came around him and took the shape of a small fox. "You have to forgive him, for you to do something like that, it hurt him more than what he is letting on. He said that you were very pretty and that was when you first met. I imagine my boy has a bit of a crush on you, you can imagine how hurt he felt when I told him you did that to him. Give him some time and he will recover it is not like you like him too." With a tear running down her face she told the fox that maybe she did.