It had been several months since Shirou had initially approached Rin, the sole living Magus of the Tohsaka mage bloodline and established a deal through a Geis in order to discover what was ailing his father and the cause of his weakening constitution as well as to gain access to what Shirou saw at the time as the only option to source a solution and cure to the problem.
Aside from Shirou's conditions there were also other aspects of the deal. He had promised to assist the Tohsaka Magus in her magical research as an assistant as well as promising not to reveal the details of any of her families magecraft. Forced into the deal, the female Magus at the time had not been happy.
Things had gotten better, while the initial confrontation of Shirou's clandestine activities and the subsequent interactions were frosty, Shirou liked to believe that they had developed some kind of a bond. Rin had initially been aghast at the concept of a Magus as her assistant that did not know the basic foundations of modern magecraft assisting her and had took on the responsibility to correct the error of the situation by imparting the basics of magecraft that the young Tohsaka had learned from her father before his untimely death in the fourth Holy Grail War.
Due to the lessons provided by her, there were many subsequent interactions and they spent quite an amount of time around each other nowadays. Shirou had settled into a routine with his partner and 'master' in Thaumaturgy. He would study under Rin as she taught him what was the basics of magecraft and through her months of tutorship, he had picked up the majority of the contents considered essential for the average mage to possess. She had in turn recognized that contrary to her initial reactions from the depth of his knowledge in magecraft, he was actually rather intelligent and had learned quickly. She had also discovered that Shirou often had unique insights into the different specific aspects of magecraft.
There had been a unique circumstance early on in Shirou's new apprenticeship that had involved both of them being curious about his elemental affinity and trying to find what it was. They had tried to use different methods to find out Shirou's affinity from tarot cards, to different spells, having Shirou use his magical energy to try to get a reactions from the different jewels that Rin possessed with different elemental affinities as well as even alchemy to try to get a hint of whatever element that Shirou possessed.
It was after much frustration that Rin finally gave up the quest to try to divine a hint of Shirou's elemental affinity. Rin was perplexed. Finding out the elemental affinity of a magus was not a difficult thing to do. Whether an individual had a single, multiple or even all elemental affinities could be discovered through a common test. Even individuals with strange elemental affinities such as Ether or even Imaginary Elements such as Imaginary numbers or Nothingness could find out their elemental affinity. Due to an individual's elemental affinity resonating with the connection to the textures of the earth, there was always a common anchor in which one would be able to find out their elemental affinity. Shirou was an exception. The only theory that Rin had was that whatever Shirou's element was, for one had to have an element, was an element that did not resonate with the world. It was not a major problem aside from failing to satisfy her curiosity, for whatever strange element Shirou had would not be a type of mystery that Rin could teach him anyway for even as an 'average one', a Magus who possessed elemental affinities to the five great elements, she still had some limits such as not possessing affinities to the Imaginary Elements.
Another part of the routine that Shirou had settled into with Rin was sparring. Rin's primary objective in sparring was to improve her skills in martial arts as well as to improve on her skills at reinforcement on herself. Reinforcement was part of the trio of basic skills also known as Material Transmutation. Material Transmutation involved the interference into the base property of an object. It involved the skills of Graduation Air, Alteration and Reinforcement. Graduation Air is considered a useless magecraft only to be used for immediate activities while Alteration while more practical was often less useful for regular uses.
Reinforcement was a different story however. Even though the reinforcement of an object was not useful by itself, the technique used in Reinforcement is extremely important as a basis for many types of magecraft. Reinforcement as a concept was to enhance the existence of the target by transferring Magical energy. Such a technique also served as the basic and most important foundation of the Tohsaka magecraft of the flowing and transferring of energy. Reinforcement was effectively what Rin was doing every time she stored magical energy into one of her jewels.
Due to the importance of Reinforcement as a technique, it was essential for a Magus to undergo regular practice with it. Aside from Reinforcement on an object, there was also Reinforcement on a living being, a much harder technique. While this was mostly ignored by the regular Magus. It was essential for a Scion of the Tohsaka family. Through Reinforcement of the human body, a Magus would be able to enhance every aspect of it, strength, speed, reflexes and even perception. For an individual slated to be involved in a high-level combat situation later on in her life, the skill was essential.
Unfortunately, it was a tremendously difficult technique with most gains from Reinforcement being negligible. This had led the vast majority of Magi to ignore this aspect of the technique and seek better and more permanent results from different rituals. It was a different situation for Rin who felt that she knew not enough about rituals and did not like the result of such rituals. As such, regular sparring practices with Shirou ensured that she would get ample practice at reinforcement on her own physique.
Another aspect of the routine and the most recent addition was one that Rin ensured that Shirou got ample practice in. Rin had initially been glad to see that Shirou appeared to have advanced mastery of Reinforcement even beyond her own level. She had planned to exploit this strength of the Emiya Magus into helping store magical energy into her jewels for use in spells.
Rin had run into a hurdle however, due to it not being her energy, she would not be able to use jewels stored with magical energy from Shirou. There was a simple solution to this problem. The solution was to have shirou store energy attuned to a specific element so that she would be able to use it. While Magi generally had an affinity to a specific or multiple elements, it was not impossible for a Magus to perform magecraft relating to other elements. The difficulty and skill involved is just greatly increased.
This solution had created a greater problem. Rin at her age of ten and a half had an extreme mastery in Jewel Magecraft even above the extent of what most Magi would achieve in their lifetimes. This was due to her elemental affinity to all elements granting her the title of an 'average one'. This was due to the nature of elements. Other than governing the base elements themselves, they also embodied the connection to similar concepts represented by the elements. Fire represents fuels and energy transfer, Earth represents the cultivating of energy and energy embedding, water represents the flow and manipulation of energy and air represented static and free energy. Due to her elemental affinities granting her a connection with these factors, the ease as well as the quality and quantity in which she could store energy into her jewels are greatly enhanced. Due to Shirou's unknown elemental affinity, the issue is reversed.
Due to not having a connection with any of the regular elements, Shirou having to convert his magical energy into one of a specific elements was significantly and greatly hampered by not having a regular elemental affinity. Even with his great skill at reinforcement, there were still many problems, one reoccurring problem was even currently happening…
"Crink" The silence was deafening. The noise in the room was non-existent akin to a void at the furthest and most tranquil parts of space. It was short however, upon what was effectively an instant but also forever through the perception of the witnesses, there was a loud shatter with shrapnel exploding, launching the constituent parts into all directions of the room and bouncing off the ground, making smaller noises every time they bounced off.
A sigh, a drop of the head, an accepted and resigned but no less devastating result had transpired once again.
"Shiiiiiirouuuu…. Could you please stop shattering and breaking my jewels? This is the fifth time this week!"
A chagrined expression, a sheepish shrug, an unavoidable outcome.
"I'm afraid not, this technique is just too hard to master for me. I don't think you seriously expected your demand to be effective in changing my skills… Did you?"
"Of course not!" She turned her head and folded her arms, huffing in a displeased manner, she then turned back and faced him again, this time with a pouting expression.
"I know this is hard for you, and as much as I would demand you try harder, I don't think that would work… But could you at least not have me dodge the effects every time I'm in the same room while you are doing this?"
"Rin… I don't think pouting is going to help… at least not by a significant margin…" Shirou looked amused as he stared at the pouting Magus now with her head down again. Shirou gained a mischievous expression and decided to diffuse the situation somewhat.
"Besides, if you pouted too much you would stay with that expression. How much would that mislead individuals that you are actually an innocent girl with nothing up your sleeves?"
"What! Shirou! You… you… you… Jerk!" Rin huffed again and stomped her way up the stairs and out of the basement workshop into her room.
Contrary to her interaction, Rin was actually much more sympathetic then she displayed. She remembered initially practicing her skills in storing energy in jewels several years back before her father's death. She used to also have problems and a plethora of different issues in this department as a child. Her greater impatience and lack of attention as a child had also served to hamper her. It was only through gaining a lot of advice and help from her father that she had been able to reach the extent of the skill she had today.
While she had some problems with the Tohsaka Jewel Magecraft when she was younger, she did not have problems to this extent. Nonetheless, looking at the progress that Shirou was making had served to console her and help forget her own embarrassing incidents in front of her father when learning her family's signature magecraft.
While Shirou's difficulties in this department had caused her a lot of issues as well as the loss of many jewels, it would eventually be worth it. Though Shirou would never be able to store as much energy nor be able to store energy of an advanced quality even if he mastered the skill, it would still be tremendously useful to Rin. Part of the Tohsaka Jewelcraft was in conserving one's own personal stores of magical energy while making sure to make the most efficient use of magical energy whenever possible.
Even with Shirou's lack of skill nor talent in this particular area, he would alleviate the burden on Rin to store some jewels with lesser and inferior quantities of magic. These were jewels that she would use for lesser and more mundane spells. She could in turn get a better variety in her arsenal by dedicating her time to jewels with higher capacities and purity of magical energy. This would allow her to have many jewels of inferior capacity and quality as well as many more jewels of superior capacity and quality. While Shirou appeared to be destroying her jewels at an unprecedented rate, her investment would eventually pay off….
It was several hours later that Rin had returned to her workshop. There was a drastic difference from her workshop several months ago and her workshop now. Even just looking at it, Rin could hardly even recognize her presence within it. The biggest difference, usually, was the presence of another Magus within her workshop. Shirou was not here at the moment but she had not registered the feeling of a tingle that would have signified that Shirou had left her house.
The basement workshop in the Tohsaka Mansion was a purpose built to be a magus workshop. It had thick walls and minimal interference with the mana of the outside world. The only entrance was the staircase out of the basement. It was a rather big room. Even bigger than the room she had designated as the sparring room several months back. It was also bigger than the living room.
Due to it only hosting the presence of a single magus, the room was usually cluttered, with an extra-large table in the middle, enchanted for durability in case of use of magecraft, many circular containers around the room, containing scrolls of magecraft from even hundreds of years ago, several chests, some locked securely with both magical and non-magical means and some without locks, books stacked in the corner, books stacked in the middle beside the table, books laid around on the floor haphazardly as well as some of the most expensive high quality jewels left around everywhere.
The room had changed majorly ever since she had granted Shirou the privilege of entering the workshop. While his main role was to assist her in her magecraft, he had often taken the time, occasionally even taking up to several hours to arrange her basement workshop into some semblance of order.
Before Shirou when Rin was left alone and with free reign across her workshop, she would often skip from one topic of magecraft to the next, learning what she wanted and what she could as she fancied. Her foundations of basic magecraft was stable, having learned and mastered it before her father's untimely demise in the fourth Holy Grail War three years ago. Her further education in magecraft was through learning with Kirei and involved getting a grasp of the theory of more advanced magecraft and then leaving her to master and conduct the practical portions herself. Being an extremely talented mage, she had accomplished her main objectives easily and was often left to boredom before Kirei's next lesson and had checked the more interesting aspects of her family's repositories and jumping off to another aspect. Due to this and not having any guests or family at home, she had developed the unseemly habit of leaving things around and not organizing them. She had still spent the majority of her time practicing spells from her magical crest and storing magical energy in jewels but she just had too much free time left and had gained this habit.
It was within the first few lessons that she was giving Shirou that he had gotten too annoyed in the environment he was going to spend much time in. In that instance, he had stopped the lesson that she was so graciously giving him and dragging her into his quests of organizing the basement workshop.
The first thing he did was source many empty shelves and cardboards from the several spare rooms of the Tohsaka Mansion and started to develop an order as to how her workshop should be organized.
At the time she was left flabbergasted about the impudence of her 'apprentice' but due to her pride as a Tohsaka Magus had to assist in organizing what was supposed to be her domain. It was a long project, spanning several days where she was left without time to do anything else before the basement workshop had turned into its current state.
The room was drastically transformed. It was now divided into three areas. The first, was an empty space spanning from the entrance staircase to the midpoint of the room. It was a space meant for the conducting of rituals as well as spells that took up more space to conduct.
The remaining half of the room was divided into two parts, one part with shelves full of books separated by a space within each shelf and the other part was organized by the containers of scrolls in the middle and the many chests stacked against the walls.
While she had thought it a waste of time and still did to an extent, she had to concede that it now provided a much better atmosphere as well as a better place to work compared to before. While she still left books or jewels around occasional, she could always rely on Shirou to clean them up.
Having finished her observations of her workshop, Rin decided to locate the presence of Shirou within her home. He had always stayed for several more hours after they finished their agendas for the day but she presumed that he was researching magecraft from her books or scrolls or cleaning up the workshop once again.
She first checked the kitchen though. Even as a girl at the age of ten, she had been able to cook at an acceptable, even great quality. She had to become self sufficient as it was troublesome to keep the presence of magecraft a secret while hiring a helper and it was also a waste of funds better used for jewels. She could have gone out for a meal everyday but it would have been an inefficient waste of a trip out when she could just buy ingredients and cook herself.
It was through an amusing incident several weeks in when she had located the presence of Shirou within her Kitchen. It was after a rather exhausting spar between them when she had wandered into a kitchen to make a cup of the tea she enjoyed and ran into Shirou whipping up a snack for himself.
She had not known that he could cook. She had not cared. There was nothing in their agreement that denoted her loaning out her kitchen. It was somewhat rude for him to use her kitchen without her permission. At the very least he could have also prepared something for her to enjoy, not that it would necessarily have been up to her standards or liking.
She had immediately prepared a reprimand until he had offered to cook up another portion and let her consume the current one he was cooking. Holding her tongue, she had remained sceptical of his skills at the culinary arts and had only taken a small initial bite to the dish. It was to her astonishment that it had tasted far better than anything she had made. While she had the funds, she never had the desire to consume a dish from a top chef but she could only think that Shirou's cooking was of that standard.
Of course, she would never compliment him out loud but she had indeed taken advantage of that incident to demand his talents when she required. He had of course naturally agreed with some disgruntled grunts of her taking advantage of him.
She had reached the kitchen and had found out that he was not in. She had then turned back and had located him in her study. His head was down, laying flat against a book on the table, he was asleep with light breathing noises. She took a few steps forward and taking care not to wake him up, removed the book from the table and his face, and taken a look at the cover of the book. It was a book that she knew came from the basement workshop but it was also one that she had not had the chance to read, having been cautioned by her father as a child.
It was a book about advanced types of curses in mythology. It was a book about real curses through magecraft and how they had been used throughout history. It involved the extreme details about the different variation of curses and how they had affected notable individuals throughout history. It was a rare tome due to it being sourced from the middle east where to study of Curses was much more advanced than the clocktower, the entity that the Tohsaka's were aligned with. The Tohsaka's would not normally care to obtain resources about such a subject but with the constant participation in Holy Grail Wars, it was best to be prepared for all eventualities. The most important fact that Rin noticed about the book Shirou was in the process of reading was that it also contained the methods to actualize curses.
Rin narrowed her eyes. When they had first made their deal, Shirou had indeed mentioned that this was the main part of magecraft within her family's repositories that he was after. It had somewhat slipped her mind but what she was looking at now seemed…. nefarious. Even if she conceded that she had indeed developed a bond with an individual she could almost call a friend, she had always maintained a bit of a distance, remembering how he had threatened her into the agreement. She decided that she could not in good conscience let him return today without at least knowing his motives for such research…
Shirou was currently in deep sleep from mental exhaustion. He had been researching for months and slowly making some headways into his main goal. To help aid his father from his suffering from the magical ailment. It was a complicated subject.
Normally, there was not much known about curses. It was not a subject actively pursued by the main magical authority in the world. Basic curses were mostly used as pranks for most curses of that level could be simply shrugged of with the activation and continuously flow of a mage's magical circuits. There was not much to be found about advanced curses, it was an often ignored subject and only actively pursued by the mage's from the middle east within their own magical cabals. There were better methods if a mage had wished harm or death on another individual.
While the basics of curses were simple and could be pursued by almost anyone with magical circuits, the further you got in, the more complicated it got. Curses run on a simple and basic aspect of magecraft. It is fuelled by mystery.
Curses are a type of Thaumaturgical foundation. A Thaumaturgical foundation is a set or pre-established rule, or a greater magic Formula or Formulae. A Magical formula is a program of magecraft where the magical circuits are activated and agitated in a specific manner so that when the command is sent towards the magical circuits, a spell will be activated and carried out.
A magical formula is used for the production of more efficient magecraft. Aside from just using raw magical energy in order to get a result or using rituals to invoke a result, a magical formula shapes an individual's magical energy into a specific manner as to use the minimal amount of magical energy in order to get a result.
Due to the world being able to be separated into substances or elements, there are different methods to shape an individual's magical energy in order to make use of an attribute of an element so as to be able to carry out magecraft efficiently. Mages can simply pour magical energy and attempt to invoke the result but it would often require the usage of too much magical energy or result in a failed or altered spell. Due to this, mages only feel comfortable with spells made with established magical formulae.
These types of magical formulae have taken years and generations of research in order to achieve and optimise the best result from the spell. For simpler and more mundane spells, there are common magical formulae that would work for every intent and spell a Magus could need with just an application of slightly more magical energy. It is only in more complicated spells that a unique magical formula was required.
Different Thaumaturgical foundations are often incompatible, only able to be used with great difficulty. This is one of the reasons western magecraft leaves an insignificant emphasis on Curses. There are also other reasons that western magecraft ignores the subject of Curses and that is due to the weakening of Curses as a Thaumaturgical foundation.
Thaumaturgical foundations run on a simple idea and truth in magecraft. If a concept can and might exist, it has existed and will exist in some form. The definite proof need not matter in such a scenario. As long as a concept exists and resides within the minds of individuals, 'faith' is produced within the particular subject. Even the rejection of such 'faith' need not matter since it still has the possibility of existing. It is through time and this 'faith' that the mystery of this particular concept grows and the Thaumaturgical foundation strengthens.
In the modern world with advanced technologies and developed philosophies of thought, Curses are abandoned and thought of as an archaic superstition. Even individuals in the past whom have not believed in curses will continue to contribute 'faith' towards it. In the modern world, individuals completely disregard and even forget about the possibility of Curses thus leading to the extreme weakening to this Thaumaturgical school.
Ironically, even mages who disregard the relevance of Curses contribute to the strengthening and continued survival of Curses by simply knowing its existence and its concept.
The reason that the Thaumaturgical school of magecraft has continued to exist is due to magic itself running on the concept of 'the ability or possibility to do the unknown'. As individuals will always strive for more and dream of greater possibilities, there will always be magic even if the word 'magic' itself is forgotten. Due to the continued existence of magic, there will always also be magecraft.
As a result of the weakening on the Thaumaturgical school on Curses, there had to be more complicated methods developed and more concepts included in order for Curses of a higher level to be conducted.
The modern version of curses was more detailed and complicated with it merging more with the concepts of spirituality than anything else. The mages from the Thaumaturgical school on curses have adapted their curses to only attack and carry out their effects on the soul rather than on the body. The curses also had to be anchored to other objects such as a puppet, doll or dying animals to carry out the same effects on an individual's soul. They have also been heard to be anchored to an individual's shadow.
It was due to the detailed studying into curses that Shirou had discovered that he had been going on the wrong path and that his past research across the months were for naught. Modern curses only attacked the soul and the more traditional curses from times long past were too difficult to activate for a modern magus. Kiritsugu's affliction was very clearly taking an effect on his body instead of his soul. This had led Shirou to only one conclusion, that whatever curse his father was suffering from was delivered by an individual from the past, most likely a spirit from the fourth Holy Grail War.
Shirou had not been too despondent, although he had suffered a major setback, there were still avenues of research to be made. Before he had met Rin, he had researched books on mythology for curses that could achieve the same effects as what Kiritsugu was suffering from but there were no specifics involved aside from simple tales and superstitions. With now the Tohsaka collection of information at his disposal, he had found a book that looked like what he required.
He had brought the book from the basement workshop into the study where he proceeded to read through the book. It was a rather gruesome true detail of what curses had struck individuals through history and their effects on such individuals. There were curses that turned their intestines into slush or curses that slowly replaced parts of their bodies with other objects. It was an exhausting read but Shirou persevered on, determined to find out what he needed. He had eventually fallen asleep with the book open through suffering from the mental exhaustion.
Shirou was a deep sleep but he slowly came out of the peaceful state from feeling a harsh shake of his shoulder. Still in a deep state of rest, he ignored the sensations until it became too violent to ignore. Still groggy, Shirou raised his head from the table, not noticing the absence of the book and came face to face with a dark black ball spell on the tip of Rin's fingers, pointing at him while carrying a harsh expression.
Alarmed, Shirou could only adopt a deer in the headlights look at Rin and question what he had done. "Have I offended you somehow recently, Rin?"
"Why were you reading that book on Curses!?"
"What motives do you have for reading such a book!?"
Not wanting to give her the real answer and still not fully awake, Shirou could only provide a half-hearted excuse.
"Arhm… I was curious…?"
It was a bad attempt, even to Shirou in his half alert state. It was apparently a worse answer to Rin.
"Don't you lie to me Emiya!" She shouted at him. She continued with a rant. "This book contains some of the darkest and most vile curses throughout history and some of the rituals to activate them! What could you possibly want with that?"
"Answer me!" She shouted again, visibly getting extremely impatient and progressively more dangerous with the spell on her fingertips.
"I was inte…" Shirou trailed off, stopping an attempt of another excuse. He then took a good look a Rin, tilting his head at several angles before his lips curved up slightly and he adopted a serious expression, seemingly having arrived at a conclusion.
Shirou then began solemnly with a serious tone. "You remembered when I told you that my adopted father, Kiritsugu Emiya had fought in the Holy Grail War?"
Rin nodded but remained silent with the spell still on her fingertips, a silent demand to continue.
"He survived the war and adopted me in the aftermath of the Fuyuki fire in the Shinto district… He was always a healthy individual but for a year now he has been getting progressively weaker in constitution for no apparent rhyme or reason. He wasn't even suffering from a disease and he had tried to hide it from me but the signs were obvious. He was most assuredly suffering from a magical ailment. I didn't think he had too much time left, maybe several years."
"Several months ago, I approached you hoping to get a source of information about such a condition from a Magus family…"
"You were trying to find the cause and a cure?" Rin asked with a softening expression but had kept the spell on her fingertips up, albeit with what seemed like a weaker input.
"I think he is suffering from a Curse, one caused by a Heroic Spirit… What I hope to achieve should be obvious…"
"Your goal does seem very innocent but what guarantee do I have that you are telling the truth? You have gotten details into some very dangerous material, some which could even circumvent your Geis and kill me."
"I… I… I could introduce you to him?" Shirou said weakly before continuing with a hurried tone. "But it would have to be in a years' time, when we go to Junior High school so that we could claim to be schoolmates… I don't want him to know what I'm doing."
Rin lowered her hand and cancelled the spell. Not providing a verbal response but responding with a nod and a smile of relief. She placed the book back on the table and walked out of the room, going back to her room so that she could think on his words. It appeared that he had her approval.
What Shirou had promised was the most that he could think of. The main prefecture that had governed the laws of Fuyuki had provided a special exemption for Fuyuki citizens affected by the fire. What it involved was an exception made for individuals to carry on their education for several years under their guardians before the infrastructure of Fuyuki was restored and ready to receive students.
Shirou had only been to the Shinto district several times after the fire but from what he could see even three years after the fire and an extensive building project had not been enough to complete most of the building projects. It would be until next year till what would be the only Junior High school in Fuyuki was constructed. Shirou had hoped that with the year he currently had left where he had ample time that he could discover a solution to Kiritsugu's problem.
Due to the changes and exception made for citizens of his age group, they would only enter Junior High school, at the age of eleven and study for five years until the age of fifteen before entering and studying for three years at the only high school that resided currently in Fuyuki City, the school that Taiga was currently studying in, Homurahara Academy…
Authors Notes:
This chapter is basically an interlude chapter spanning the details of what had happened in the few months since the last chapter.
Throughout this chapter my goals were basically to develop Rin and Shirou's relationship more through a natural progression of months and settling into routines.
More lore is also provided as well as more generic basic laws for readers less familiar with Fate. I also go into a bit of detail of their routines and skill levels and why Rin is such a talented Magus even at her age of ten. I'm boosting up Shirou's ability compared to canon Shirou throughout my story but more detail into Rin's magecraft as well as a greater appreciation of her skill was nice to include. The lore into the Magical system of my story if also given and the part about elements will me important later. The first part is basically a summary of the several months that have passed.
We see Shirou's problem with the aspect of 'Tohsaka Magecraft' of transferring and pouring magical energy even with his immense skill of reinforcement on objects. We also see how Shirou's and Rin's bonds have advanced and also some more incidents of the months in between.
Rin discovers Shirou's research and gets suspicious as well as a tiny bit hurt that Shirou could be researching on ways to harm her.
We skip back to Shirou's side to find out his progress on finding a cure to Kiritsugu's cure as well as more lore about what Curses are and his progress in his quest. We find out more detailed lore which is completely canon but expended with other aspects of canon lore from the different franchises of Type-Moon that are technically in the same universe. We also discover more details on the Curse of Angra Mainyu and why what Shirou is reading had Rin so alarmed.
Rin questions Shirou and Shirou sort of makes and excuse but eventually decides that he knows Rin's character well enough and he can trust her. Rin discovers Shirou's quest and has an internal sigh of relief that Shirou is actually her friend and not actively seeking to harm her. She discovers more about Kiritsugu Emiya and Shirou makes a promise to reassure her that he is telling the truth about his goal. This effectively breaks a barrier between them where they can actually be friends instead of just Magical friends that tease each other.
An explanation is given as to why they aren't currently in school, some lore on the consequences of the Fuyuki Fire as well as setting up a timeskip to when they go to school in the next chapter.
Some answers to questions:
Shirou is connected to the Root.
The pairing is definitely Shirou/Saber when we reach that point
Shirou's Origin is sword and 'concept's' with 'concepts' being slightly stronger due to it being his Original Origin. His element is 'concepts' governing aspects outside of the world instead of inside of the world like regular elements. Due to Shirou's Origin of 'sword' being more as in he embodies the concept of a sword due to Avalon, his element of 'concepts' governs a 'concept of a sword' thus making him basically a dual incarnation even though he doesn't have 'sword' as an element.
This Shirou doesn't have guilt from being the only survivor of the fire since this is an alternate universe. This Shirou is actually arguably worse than Kirei since he lost his memories from the fire and is empty but without morals and social awareness due to the lost memories from the fire. He is internally good but without the knowledge of morals. Kiritsugu has chats about being a hero of justice but doesn't actively educate Shirou about morals since those go out of the window in Kiritsugu's life.
He is aware of Kiritsugu's childhood dream of being a Hero of Justice but his obsession is with Kiritsugu as his savior and father, hence his current quest.
Also some clarification about his current skill level:
Shirou is a pretty good swordsman, an amazing one really. His current skill and only in skill is about the exact level of Shiki Ryougi in swordsmanship but without actual combat experience and enhancement except for canon Shirou's level of reinforcement at this point but he's also ten, so...
He's pretty decent in magecraft but due to his element being 'concepts' will have trouble with most things until he knows how to utilize 'concepts'. He won't know how to use his connection to the Root for a long while yet.
His knowledge of magecraft in theory is equivalent to Rin with her knowing more specific stuff in more topics but Shirou knowing more intricacies of specific parts of magecraft due to his Origin instincts. His knowledge of base magecraft is the same as Rin.
Also, there have been over a hundred reviews posted on this story... That's fine, I like reviews, they get me to consider things I may have missed. Please do review more.