Upon learning that Sakura had become the Grail War's newest Master, Kariya was momentarily stunned. However, he quickly regained his composure. Zouken's high regard for Sakura had always hinted at her immense magical potential, far exceeding Kariya's own.
Moreover, with Berserker as her protector, Kariya felt no concern for Sakura's safety. Had he not been careless, had he summoned Berserker to his side the moment he sensed Kiritsugu Emiya, he wouldn't have been killed. Now that Sakura was involved, Kariya pulled her close and began explaining the essential knowledge a Master needed to survive the Grail War.
"Alright, Kariya."
Ailin interrupted by clapping a hand on Kariya's shoulder. "Sakura's only six years old. Do you really intend for her to participate in this war?"
Kariya, still mid-explanation, blinked, momentarily confused. "Berserker, the Command Spells appeared on Sakura's hand. Only she can use them to amplify your power. How can you fight without her on the battlefield?"
"Hahaha, Kariya, you underestimate me. The only truly challenging opponent in this war is Archer. I can defeat the other Servants without even unleashing my most powerful Noble Phantasms. Sakura's presence is… inconsequential."
Kariya paused and considered Ailin's words. He was right. Against any Servant other than Archer, Berserker was overwhelmingly powerful. In those battles, the Master was the Servant's greatest weakness, a vulnerability to be exploited.
But then Kariya shook his head. "True, Berserker, but against Archer, if his Master uses Command Spells to amplify his power, you will need Sakura's as well. Otherwise, you risk defeat."
Ailin couldn't refute this. Sakura's magical energy, now his source, had enhanced his base attributes and significantly increased his endurance compared to when Kariya had been his Master. However, against Gilgamesh, the outcome was uncertain. If Tokiomi Tohsaka used Command Spells to amplify Gilgamesh's power, Ailin might indeed lose.
"Besides, Berserker, during this war, I believe Sakura is safer by your side than mine." Kariya then recounted his encounter with Kiritsugu Emiya, how he'd been killed.
"Magi usually avoid involving ordinary humans in the Grail War. But the moment that man called out my name, I knew he was a terrorist, someone who would stop at nothing to achieve his goals. I can't guarantee he hasn't already investigated this place, that he doesn't know about Sakura's existence. And I have to admit, without magical energy or my Worm magecraft, I'm no match for him."
He didn't hide his powerlessness from Berserker. He had died once. He knew the dangers a Master faced. And as long as Berserker remained active in the war, Kiritsugu would undoubtedly find him again. He couldn't protect Sakura alone. Only Berserker could safeguard her, and perhaps, with Sakura's support, even win the war.
"I see."
Ailin stroked his chin thoughtfully. Two Masters in this war might target a child. One was Kiritsugu Emiya.
Kiritsugu who was driven by his ideals, would eliminate anyone who stood in the way of "world peace." If Kiritsugu attacked while Ailin was absent, Kariya and Sakura would be in grave danger.
If Kiritsugu confronted them directly, Sakura could use a Command Spell to summon him. In a direct confrontation, Kiritsugu wouldn't stand a chance. But if he used a sniper rifle, like Maiya Hisau, they wouldn't have time to summon him. While Ailin had attacked Kiritsugu's location with a slash after reviving Kariya, Saber's continued presence suggested Kiritsugu had survived.
"Very well, but if I have to fight while carrying Sakura, my fighting style will have to… adapt."
Ailin suddenly smiled. He was summoned as Berserker, but his previous battles hadn't been particularly… berserk. Against Gilgamesh, he'd used his Zanpakutō and the King's Treasury, more like an Archer.
Against Artoria and Diarmuid, he'd relied on pure swordsmanship, like a Saber. Only his brief clash with Gilgamesh after unleashing Nozarashi had resembled a Berserker's fighting style.
But that fight had been interrupted by Kariya's death. Now, with Sakura by his side, he would either have to rely on his King's Treasury, or unleash the abilities of his Zanpakutō, much like Gilgamesh.
Despite her age, Sakura possessed far greater magical energy than Kariya. With Kariya as his Master, Ailin had carefully considered each Zanpakutō's release, relying mostly on his own spiritual pressure, fearing he might drain Kariya's life force. But with Sakura, even unleashing multiple Bankai wouldn't be a problem.
Ailin asked, "So Sakura, would you like to experience the atmosphere of the Grail War tonight, or shall we begin tomorrow?"
Sakura looked at Ailin, then at Kariya, unsure how to respond. Since she could remember, decisions had always been made for her. Toys, clothes, even being sent to the Matou family… no one had ever asked her opinion. Now, faced with a choice, she felt lost.
"Sakura, Uncle Kariya understands all this is difficult to accept. But as a magus, you will have to face many enemies. I'm not strong enough to protect you. You have to learn how to fight while Berserker is still here." He smiled encouragingly. "Go. Berserker will keep you safe."
Sakura nodded and walked towards Ailin, reaching out to grasp his captain's haori. Ailin scooped her into his arms and leaped into the air.
"Beautiful, isn't it?" he asked, hovering above Fuyuki City, the cityscape spread out beneath them like a glittering tapestry.
While he agreed with Kariya's reasoning, Ailin didn't want Sakura to be traumatized by the war. He wanted her to experience the world's beauty. If they had to fight, he would choose Zanpakutō with aesthetically pleasing abilities, something a child would appreciate.
"Wow…"
Though she was initially apprehensive, Sakura gasped. Her eyes were wide with wonder as she took in the breathtaking view. Aside from magi with familiars capable of flight, she was likely the first person to see Fuyuki City from this perspective.
Ailin slowly flew across the city, allowing Sakura to experience the vibrant energy that was absent from both the Tohsaka and Matou residences. While the night held its share of darkness, Ailin carefully avoided those areas, shielding Sakura from the city's underbelly.
However, before they could complete their tour, Ailin noticed something in the alley below. A small girl with dark hair, clutching a red gem, seemed to be searching for something. A twin-tailed girl alone wouldn't have caught his attention. But in Fuyuki City, at this time, a twin-tailed girl with a gem… it could only be Rin Tohsaka, Sakura's older sister, heir to the Tohsaka family!
He suddenly remembered. During the Fourth Holy Grail War, Caster's Master, Ryūnosuke Uryū, was a serial killer who targeted children, seeking "beauty" in their deaths. Rin, trying to save her friend, had defied her father's orders and snuck out with a gem that could detect magical energy. Had Kariya not intervened, Rin might have become another victim. But this time, Kariya had summoned Ailin and been killed by Kiritsugu Emiya. Had Ailin not taken Sakura on this flight, he might not have encountered Rin.
"That's… Sister."
Sakura's eyes lit up when she saw Rin. But the light quickly faded. She couldn't understand why she'd been sent to the Matou family, forced to endure Zouken's cruel training. She had cried, screamed, and pleaded for help. But her parents, even Rin, hadn't come. Then, Uncle Kariya and Berserker had arrived. Finally, Grandfather was gone. Seeing Rin again, Sakura had expected to feel joy. But a deep understanding settled over her. She no longer had the right to call Rin "Sister." She was a Matou now.
"Berserker," Sakura tugged on Ailin's haori. "Let's go. Let's see the other side."
"Are you sure, Little Master? I sense traces of a Servant's magical energy near that girl. If she continues, she might be caught in the crossfire, become an innocent victim."
"What?" Sakura's grip tightened. "Berserker, you have to save her."
"Don't worry, Little Master," Ailin reassured her by gently patting her head. "If I hadn't seen her, I wouldn't interfere. But now… how can I ignore her?"
His words applied not only to Rin, but also to Caster and his Master. Ryūnosuke Uryū and Gilles de Rais were pure evil. He could have let them live a while longer. But now that he'd found them, he would end them tonight. With that thought, Ailin vanished with Sakura in his arms and instantly appeared before Rin.
"Who?" Rin gasped and was momentarily blinded by a sudden shadow looming over her.
To her alarm, the gem in her hand grew intensely hot, almost burning her. The gem, taken from her father's workshop, reacted to magical energy. The stronger the energy, the hotter the gem became. It was this gem that guided her, allowing her to follow the traces of Gilles de Rais's magical energy on Ryūnosuke Uryū, leading her to their location.