Kiritsugu dodged the Black Keys Amakusa threw. He was extremely familiar with the Church's attack methods, as he often clashed with Church personnel while on missions. However, though his movements seemed effortless, the Black Keys thrown with a Servant's strength were faster and more lethal than any opponent Kiritsugu had ever faced. If he hadn't accelerated with his unique Time Alter, he would have had no chance of dodging this attack.
"Acceleration magic?" Amakusa easily saw through Kiritsugu's trick. "Rest assured, I won't miss next time. I never expected that the Einzberns of that world would hire the Mage Killer to obtain the Holy Grail. Has the Einzbern family over there fallen as well?"
"Don't you know what a Soul Crystal is?" Kiritsugu said, but his hands never stopped moving. To avoid close-quarters combat, he proactively threw out several smoke bombs. The opponent had been fighting him using Church techniques, but hadn't shown much of their own Servant abilities. They were underestimating him too much, yet he himself had no trump card. In that case, he could use this to expand his advantage. "You're the one who has fallen. How could you save the world with something like that?"
"Ignorant!" Amakusa couldn't possibly stop now that he'd come this far, especially since the Third Magic had already proven the feasibility of soul preservation. "That's exactly why I need to guide you. The Enemy of Humanity appearing here to obstruct me is the best proof. This is a salvation, and no one can stop it. You, who sell your life to a Beast, will never understand!"
Amakusa proactively closed the distance between him and Kiritsugu. To him, this tear-inducing smoke had no effect at all. The obstruction of vision couldn't stop Amakusa's senses. The rapier formed of Black Keys surged toward Kiritsugu's position.
It hit. However, the feeling was wrong.
The smoke cleared slightly, and Amakusa saw only a small pink skirt, followed by a hairy leg that even white stockings couldn't fully conceal, kicking directly at his face.
"?" Amakusa was greatly shocked. He instinctively took a step back, using the impact to recreate the distance between them.
As the smoke cleared, Kiritsugu Emiya, wearing a Magical Girl outfit, stood tall and straight in place, pink magical power visibly swirling around his body.
Irisviel involuntarily looked away from Kiritsugu's appearance. This was a bit... embarrassing for her. However, Kiritsugu Emiya, who had already gotten past this psychological hurdle, was surprisingly open about it. As long as he could obtain power, mere embarrassment and mere dignity were things he was willing to discard.
"No, seriously, a Magical Girl? What kind of joke is this?" Amakusa looked at Kiritsugu in disbelief. Setting aside how eyesore-inducing it was, he couldn't comprehend why such a thing would actually appear. Shouldn't this kind of transformation that suddenly skyrockets combat power only exist in anime?
"This is exactly the specific function of the Third Magic, the Soul Crystal, that you're so obsessed with." After his initial hesitation, Kiritsugu had explained the matter of the Transformation Jewel to his wife. As an Einzbern, Irisviel immediately discovered that this was actually a Mystic Code driven by the Soul Crystal. The Age of Gods Magecraft built into it was already extremely powerful. With the nearly unlimited output of magical power from the Soul Crystal, its effectiveness was further enhanced by around 50%. "The Soul Crystal cannot save humanity at all, it merely turns them into magical power fuel!"
The Third Magic can indeed maintain the existence of the soul, but unlike Jiang You's crystallization (refer to a certain ending of Sakura's route in HF), it requires a special environment to sustain the soul, and then finding a vessel to perform a reincarnation of sorts. However, not only is it difficult to find such a vessel, but it also cannot fit perfectly like the original physical body. It is merely a makeshift measure to save the soul after the body collapses.
"How could the Third Magic be such an inconvenient thing? During these sixty years, I have constantly analyzed the manuscripts of the Third Magic left behind by the Einzberns, and I understand it better than anyone else!" Amakusa was even more certain than the Einzbern family that the Third Magic could save all of humanity. He was this kind of person even before his death, let alone after becoming a Heroic Spirit. He would only believe himself. "The thing in your hands is merely a product of the Third Magic, it doesn't represent the Third Magic at all!"
"You claim to save humanity, yet you're just talking to yourself, completely ignoring the consequences!" Kiritsugu was also furious. If it weren't for the fate of his wife's family, he would have never bothered to say so much to this man. "You are the true enemy of humanity!"
The physical enhancement and magical power provided by the Jewels allowed Kiritsugu to maintain his Time Alter for an extended period. His speed instantly multiplied several times over. If measured by Servant Parameters, it would be around B+.
The sudden surge in speed caught Amakusa off guard for a moment. The Magic Wand in Kiritsugu's hand smashed down toward Amakusa's head like a sledgehammer.
Amakusa finally reacted, but instead of using his Black Keys to block, he raised his right wrist as if intending to take the hit with his body.
Kiritsugu sensed something was wrong. He had infused this attack with a massive amount of magical power, using quantity to force a qualitative change that achieved an effect similar to a low-level Mana Burst. Normally, if one didn't dodge, even a top-tier Servant wouldn't be able to withstand this blow head-on. However, he was unwilling to miss this opportunity.
"You fell for it!" Amakusa revealed a triumphant smile. His hands were actually his Noble Phantasms, master keys that could connect with any Magic Foundation to use any Spell. The right wrist, Guilty Retaliation, was responsible for auxiliary combat tasks such as future sight. As long as it wasn't a top-tier Mystic Code or Noble Phantasm, he could perform reverse-effects on it, weakening or even decomposing it (as seen in the anime when he blocked Jeanne's self-destruction). Kiritsugu's act of delivering his Mystic Code to him was nothing short of digging his own grave. "Handing me this ridiculous..."
Before Amakusa could finish speaking, the Magic Wand smashed solidly onto his wrist. The intense pain, accompanied by the sound of bones shattering, made Amakusa groan.
Kiritsugu, of course, would not miss the chance to press his advantage. The target of this attack was Amakusa's head.
This time, Amakusa didn't dare to act arrogantly. He directly summoned his tachi, the Mikike Tenta, to block the attack.
"What a joke! How is this possible!" Amakusa stared incredulously at the Magic Wand in Kiritsugu's hand. Was this thing a product of the Age of Gods? Were there Magical Girls in the Age of Gods?
PS: The original setting for Amakusa's Noble Phantasm is: Although it is a convenient Noble Phantasm, it is completely useless against a top-tier Magus like Caster Medea. The "soft setting" couldn't pass Caster Medea; Amakusa was truly pitiful.