Matou Decimation (1)

Kiritsugu was taking an afternoon nap. His son, Shirou, had been training with him very intensely. Today was a day off, and Shirou would spend it with his friend, Hiro.

For Kiritsugu, it was also an important respite. With so much Magecraft training, he was constantly reminded of the many 'sins' that he had committed over the years.

From his first encounter with Shirley, to when she turned into a Vampire, to when he became a Magus, to the most recent Fourth Holy Grail War.

But what he was reminded the most about was Irisviel and his daughter, Illyasviel. He desperately wanted to see Illya, yet he couldn't. He knew he was going to die soon. But for some reason, his body wasn't getting weaker anymore.

It was almost as if… someone was healing him. With this new hope, he had continued to disregard his own guilt and taught Shirou as much as he could. Although transferring the Magic Crest would be impossible, he still wanted to pass down a legacy.

"Phew…. Guess I'll watch some TV now."

Kiritsugu got off his bed and attempted to go to the dining room, only to fall onto one of his knees.

"T-This Prana… this scale is… humongous! When was there such a Magus in Fuyuki City? The direction… Matous?!"

Kiritsugu knew of the Matous' inherent evilness from the Fourth War. As such, despite not being in his prime anymore, he hurriedly found his Contender and rushed towards the other side of Miyama Town.

---

While Kiritsugu was rushing towards the Matou residence, Shirou was already there. In fact, he was the cause of the sudden spike in Prana.

Although their bloodline had declined, the Matous had still managed to produce some reputable Magi. They also had numerous Magi under their employ, and they were all concentrated in the area around the Matou residence.

Not to mention, Shirou knew that Kotomine and Gilgamesh would probably be snooping around this area as well.

Therefore, he intended to show his might straight from the get-go.

Despite that, the only true threat to Shirou right now was Zouken. Kariya was already dead from the Fourth War, and Byakuya was a weakling who was frightened at the mere presence of Kiritsugu.

Shinji was useless, and Sakura's Magic Circuits had already been partially destroyed. The Crest Worms had only been within her for two years, so they should be easy enough to remove with Kiritsugu's help.

Also, Shirou was privy to a small bit of information that only Zouken himself would know…

The fact that Zouken's main body was actually a small worm next to Sakura's heart.

As for how he would remove it, that was the difficulty. He could very well just change it into a Sword using his Origin Bullets, but then it would be like having a ticking time bomb in Sakura.

The other option would be to have Kiritsugu 'Sever' it from her body, then changing it into a sword. The problem still lay in how to get it out though.

Shirou had been contemplating it for a long time. He finally stumbled upon the correct answer.

He would bring her into his Unlimited Blade Works. There, he would have full control over all the swords he's ever created or come across. With that, removing Zouken's body would be extremely easy.

As for what happens after that… it's not something a normal 9-year-old should have thought about.

Finally prepared for the assault, Shirou launched his attacks.

There were multiple ways to do so. He could form a Broken Phantasm, blowing up the entire mansion. However, that would be no fun. Shirou wanted to see the Matous writhe in pain, much like how Kayneth had when Kiritsugu severed and bound his Magic Circuits.

Fully expecting an enemy attack, Shirou proceeded to the front of the Matou residence, where he was greeted by a quivering Byakuya.

"S-Stop! D-D-D-Don't trespass any further!"

Shirou had a savage smile on his face. His smile was warped to the point of reaching his ears, and his teeth were fully showing.

Byakuya, who saw such a smile, couldn't speak another word. Accompanied with the smile was also an intense killing intent.

Shirou hadn't just been training endlessly over the past year. He had also been utilizing his saving and loading feature, going on rampages to get over the fear and guilt of killing.

Just before getting caught, he would load the save file, and do it all over again.

After the first few times of puking up everything in his stomach, he started getting used to it.

At some point, all of the killing became a release for him, and he started craving for more.

However, it was at that point that the people around him started raising concerns.

Especially since he was just a 9-year-old kid to them. Their concern woke him up from his absurdity. From then on, he stopped the killing, and instead would release his frustrations within his Unlimited Blade Works. Since Avalon was there, no damage could be done.

And Byakuya, who was on the receiving end of all of this, definitely had the living daylights frightened out of him.

Imagine a 9-year-old child looking at you with bloodlust, knowing full well that they could crush you into meat paste with a click of his fingers.

Something like Tanya Degurechaff.

And so, Byakuya was the first to die. Without so much as a movement, his entire being had been converted into a sword. The sword plopped onto the ground with a smooth 'clang' sound, just waiting to be picked up.

Regardless of its use, Shirou traced the sword anyway. After all, even a weak weapon was still a weapon. Combined with the flaw removal, it might actually prove useful.

His Origin Bullet Magecraft hadn't been mastered yet, so the uses were limited. He would leave the uses for the most important people.

After having breached the entrance, Shirou continued moving forwards.

"Who are you?! Stop!"

"Stop!"

Countless Magi with a Matou affiliation rushed towards him with weapons and several Mystic Codes.

Shirou stood tall, with his arms wide open. His hands were outstretched to either side of his body, and… as if he was gripping something.

A blue handle slowly formed within both hands, with the material inching ever further outwards.

Soon, a brilliant golden sword had been formed in both of Shirou's hands. A blue handle, a thick golden crossguard, a golden blade, and a short inscription.

The Sword of Promised Victory, Excalibur.