After listening to Shinji's account, Kariya fell into silence. He didn't doubt the truthfulness of what Shinji said. As soon as Shinji started speaking, Kariya knew that he was telling the truth. He was simply shocked by that segment of history that spanned two thousand years, starting from before the Common Era."
"The executor of miracles, the mysterious third magic, the grand ambition to aid humanity, the plan of 1800, the alliance of the three major families, the war that occurs every 60 years. Just the thought of his involvement in all of this made Kariya experience an indescribable mix of emotions, ranging from excitement and bitterness to fear and worry. Of course, there was also the surge of hot-bloodedness that comes with being a man."
"After Shinji finished recounting the origins of the Holy Grail War, he didn't say anything more. He simply drank his water silently, waiting for his uncle to digest everything he had heard."
"Kariya possessed a determination that ordinary people didn't have. When faced with a problem, he rarely got caught up in indecision or evaded it. Instead, he would quickly analyze the problem, decide what he needed to do, and never regret his choices."
"When he was young and wanted to leave the Matou family, he immediately ran away from home and was never heard from again. A year ago, upon hearing that Sakura was going to enter the Matou family, he rushed back immediately, even willing to sacrifice himself to save her from the worm's nest. When he learned that Shinji would participate in the Holy Grail War a year later, he decided to take the role of the Matou family's Master and defeat his archenemy, or at least, that's how he saw it."
When he knew that Sakura would inevitably enter the world of magecraft, he grew up in the shortest amount of time and supported the Matou family, which was on the verge of decline after losing its only magus.
Therefore, Shinji firmly believed that when Kariya learned the truth, he would quickly come to understand it because--
"It sounds like it doesn't have much to do with me?" This was the first thing Kariya said after his silence, revealing the truth after dispelling the fog.
"I knew Uncle would say that." Shinji was not surprised at all by his uncle's response.
No matter how profound things were hidden behind the Holy Grail War, they had little to do with Kariya. He was just a magus who had recently shed his novice status, lacking the pride and persistence of traditional magus. The origin, magecraft, and all that were too distant for him. He only wanted to live each day well, silently watching over Aoi and Rin from afar, pouring all his efforts into Sakura. That alone brought him happiness.
"I'm telling you all this because Uncle should know everything, as the heir of the Matou family's magus lineage. The head of the Einzbern family, Acht, and the head of the Tohsaka family, Tokiomi Tohsaka, know it, and of course, you should know it too."
Although Shinji's father, Byakuya Matou, was the family head, only Kariya, who inherited the Matou family's magic crest, was qualified to know the truth. The world of magecraft ultimately did not belong to his father, Byakuya, an ordinary person. Sakura was still too young, but it wouldn't be too late to tell her in ten years.
The reason it wasn't mentioned before was that Shinji didn't yet understand Kariya and Kariya himself wasn't mature enough. But now, Kariya had inherited the magic crest and become a magus, participating in the Holy Grail War. Since he had seen Irisviel, who looked identical to Justeaze Lizrich von Einzbern, and witnessed Scáthach's entrance as a Servant, it was time to reveal the truth.
More importantly--.
"The decision to conceal the identity of Lady Justeaze and Sensei was mine. I hope that after knowing the truth, Uncle won't harbor any resentment towards Sensei and Lady Justeaze. I consider them as family."
Upon hearing Shinji's words, Kariya also expressed his stance.
"Our family has come this far thanks to Sensei and Lady Justeaze. Regardless of who they are or what their motives may be, I will always be grateful. I believe that my elder brother and Sakura share the same sentiments. Our family is different from other cold-blooded magus lineages."