Souta sat on the edge of his futon, his head cradled in his hands. Hours had passed since he first awoke in this unfamiliar life, yet the weight of the situation refused to settle. His mind remained a storm of conflicting realities—the life he had lived as a normal high schooler and the one implanted in his mind as an orphan in Fuyuki City. The memories of this 'new' life weren't false; they felt as real as his past, but the knowledge of the Fate/Zero timeline ensured that he couldn't blindly accept them.
He took a deep breath, forcing himself to focus. He needed to sort through his memories, separate what was useful from what was irrelevant.
Alright. What do I know?
His new identity was that of an orphan who had come into a significant inheritance. He wasn't affiliated with any mage family, which meant he had no immediate magical lineage to rely on. However, despite being an orphan, he had access to resources—his house was paid for, his finances were stable, and there were no pressing obligations tying him down. In short, he had freedom.
Freedom to act. Freedom to change things.
His hands tightened into fists. The Fourth Holy Grail War was a brutal conflict, one where only a select few made it out alive. He knew the fates of the participants—Kiritsugu's inevitable downfall, Kirei's ascension into the war's true villain, and the ultimate corruption of the Grail itself. If he played his cards right, he could avoid being collateral damage.
But simply surviving wasn't enough. If he had been thrown into this world, he had to assume there was a reason.
That's when the idea struck him.
Caster's Master. I need to replace them.
In the original timeline, Caster was Gilles de Rais, summoned by Ryuunosuke Uryuu, a serial killer with no real grasp of magecraft. Their chaotic presence in the war was an anomaly—Caster's sadistic hunts had drawn the attention of every other faction, forcing the Servants to cooperate in wiping him out. If Souta could remove Ryuunosuke before he summoned Caster, he could take his place in the war under better circumstances.
But if I do that… who will I summon?
He grimaced. The thought of summoning the original Caster disgusted him. Gilles de Rais was a monster, even before the Holy Grail War twisted his already depraved mind. Souta had no intention of working with someone like that.
No, if he had to summon a Servant, it had to be someone strong. Someone he could rely on.
The most famous Caster in Fate was, of course, Medea. If he summoned her, she would be a powerful asset—her knowledge of magic, her ability to create bounded fields, and her ability to betray her Master if she deemed them unworthy were all factors to consider. But she wasn't the only legendary mage out there.
What if I summon Solomon? Or Merlin? No, that's too absurd—this isn't Grand Order.
His mind raced through other possibilities. There were countless legendary magicians in human history. Figures like Morgana le Fay, Nicolas Flamel, Paracelsus, Thoth, Zhuang Zhou—mages whose reputations were as grand as their mysteries. Even figures from mythological traditions, such as Väinämöinen from Finnish legends, Shennong from Chinese mythology, or even Hermes Trismegistus, could theoretically appear as Casters.
With my luck, I'd probably summon someone ridiculously powerful… or someone completely unhinged.
One thing was certain—he wasn't summoning someone from a Lostbelt. That would be cool, sure, but he wasn't about to gamble on bringing in an entity that the world itself rejected. The last thing he needed was a Servant whose very existence would destabilize reality.
Still, without a catalyst, he had no control over the summoning. The Grail would decide based on compatibility, and that was an unpredictable factor.
First step—track down Ryuunosuke and prevent him from summoning Caster. Second—summon my own Servant before anyone notices something is wrong.
The plan wasn't foolproof, but it was a start. With a determined breath, he stood up and stretched. If he was going to manipulate the events of the Holy Grail War, he couldn't afford to sit around in his house and wait. He needed information, supplies, and most importantly, a means of acquiring a catalyst.
As he moved toward his desk, he let his mind drift back to the events of Fate/Zero, recalling the details of the war's major players. If he wanted to stand a chance at survival, he needed to consider the threats ahead.
Kiritsugu Emiya. Ruthless, pragmatic, and a master of modern warfare. If there was anyone who embodied the 'ends justify the means' ideology, it was him. If Souta attracted his attention too soon, he'd be eliminated before he even got a foothold.
Kotomine Kirei. A man who, at this stage, was still trying to understand his own emptiness. He was dangerous, but his true potential wouldn't awaken until he was pushed toward Gilgamesh. Avoiding him for now was the best course of action.
Gilgamesh. Souta exhaled sharply. Stay the hell away from him.
The remaining Masters varied in threat level. Waver Velvet was inexperienced but had Iskandar, a powerful Servant with a commanding presence. Tohsaka Tokiomi was competent but too arrogant to consider unorthodox threats. Kariya Matou was desperate and dying, but his Berserker—Lancelot—was a relentless force of destruction.
Souta rubbed his temples. His greatest advantage was that no one knew he existed in this war. If he played his cards right, he could remain in the shadows, striking only when necessary.
I need to move fast.
With newfound resolve, he grabbed his coat and headed toward the door. His first task was to locate Ryuunosuke before he carried out his usual murders. If he could intercept him before he summoned Gilles, he could take his place in the war and summon a Servant of his own choosing.
The pieces were moving. The war had yet to begin, but Souta was already rewriting fate.