That Assassin is our enemy.
When Chiron pointed out this fact, the room fell into silence—especially Achilles, who couldn't help but frown.
Indeed, Sakatsuki would be an extremely reliable ally, just as he had been when he was with the Red Faction. He had executed Black Faction Servants like Frankenstein and Vlad III, even seizing the Greater Grail itself.
Once such a person became an enemy, even the wisest sages and most tenacious warriors would find themselves troubled.
"This is troublesome..." Achilles muttered to himself. In his mind, Sakatsuki—who had manipulated the entire Holy Grail War from the shadows—was already on par with the legendary strategist Odysseus from his era, if not surpassing him in combat prowess.
But could he himself, along with the Black and Red Factions, remain as impregnable as the walls of Troy?
Achilles had no answer.
"Since Sakatsuki sought out Sieg tonight, he must be trying to recruit her, right?" Karna suddenly spoke. "Do you think Sieg will agree?"
"Probably. After all, he's the mentor who gave her power and shaped her existence," Achilles sighed. "It's just unfortunate we can't address this openly. We've lost the initiative and can only watch Sakatsuki act."
As Achilles said, Sakatsuki's true identity was known to only a few. Even if those aware of the truth came forward, whether others would believe them was one matter. Even if they chose to trust and immediately engage in battle, whether the combined forces of Black and Red could defeat a fully prepared Sakatsuki was another question entirely.
Perhaps Sakatsuki, recognizing their current predicament, felt emboldened to return to the Black Faction openly and reclaim his pieces without fear.
This overt scheme... Achilles slammed his fist against the wall in frustration. Just then, Karna spoke thoughtfully.
"But I've heard that not only Sakatsuki, but also Black Faction Servants like Archer have helped Sieg considerably. Moreover, isn't the Black Faction currently reconciled with the homunculi?"
Hearing this, Chiron's expression shifted slightly as he stood up.
"Karna is right. Knowing Sieg as I do, there's a chance she might refuse. And if she does—"
"That means both Sieg and Black Rider could be in danger!" Achilles instantly grasped the implication. He leaped to his feet, flung the door open, and rushed out, with the other two Servants close behind.
"Ah—!!!"
The moment they stepped outside, the three were met with an ear-piercing scream—so loud it stirred the entire floor. Masters were jolted awake from their dreams, while homunculi scurried about nervously, trying to locate the source of the commotion.
The three Servants exchanged glances. They easily identified the origin and simultaneously turned toward the room across the hall, their expressions perplexed.
"That voice... Ruler?"
"Why is she in Sieg's room?"
Before they could finish, Sieg's door burst open. The Saint, her face burning red, stumbled out with her hands covering her cheeks, then bolted down the hallway and vanished into the distance—leaving the bewildered onlookers utterly confused.
"...What just happened?"
The scene rewinds to a few minutes earlier, the moment Sakatsuki entered Sieg's room.
"I'll get straight to the point, Sieg." Sakatsuki leaned back on the sofa, appearing much more relaxed than he had been in the Hanging Gardens. "I'll need your help during tomorrow's decisive battle."
Sieg, who was brewing tea, tilted her head in confusion. "But we're both members of the Black Faction. Helping each other is only natural, isn't it, Teacher?"
"You're not understanding me, Sieg." Sakatsuki raised his eyes, their color transforming into a profound iridescent blue. "The one asking for your help is 'me'—not any other entity."
Under this subtle yet undeniable pressure, Sieg's pupils constricted sharply. Without needing further explanation, she suddenly comprehended Sakatsuki's meaning. As she gazed at her teacher's expressionless face, she momentarily glimpsed the original assassin he once was.
Beneath the dark night and dense forest, the homunculus girl who had struggled back from death's door opened her eyes to see the young man who had saved her. Her heart filled with gratitude, only for it to freeze instantly upon meeting those icy iridescent blue eyes. It took her a long moment to remember to voice her thanks.
That gaze had been ruthless, cold—as if appraising merchandise, evaluating her worth.
If deemed valuable, he would make the purchase. If not, he would discard it without hesitation.
Ducklings imprint on the first creature they see as their mother, but when Sieg first saw Sakatsuki after her rebirth, her immediate reaction had been fear. Only in subsequent encounters, as Teacher Sakatsuki grew increasingly gentle, did she choose to forget that initial impression.
Now that she thought about it, when exactly had warmth appeared in her teacher's eyes?
The iconic Type-Moon imagery that surfaced in her mind was quickly suppressed. Sieg knew this wasn't the time for such thoughts—if her answer displeased Sakatsuki, this teacher wouldn't hesitate to act regardless of their relationship or her status.
With an assassin's agility, Teacher Sakatsuki could easily restrain or even kill her before she could summon her Servant.
Think. Think desperately. Understanding why she hesitated and wavered, she needed to find the sole path leading to a happy ending—
"...But I still can't agree to your request, Teacher."
"Oh?" Sakatsuki's gaze grew colder. "Your reason?"
The pressure intensified like an iceberg bearing down. Sieg gasped for breath, her growth since birth allowing her to barely withstand the hero's killing intent.
"Because... you told me I needed power."
"Indeed I did." Sakatsuki crossed his arms. "But what does that have to do with joining me? No one can grant you more power than I can."
"Then... what would be the cost?"
"Oh?" Sakatsuki narrowed his eyes with interest. "This wasn't covered in my lessons. Interesting. Continue, my student."
As the oppressive atmosphere lessened, Sieg panted heavily before speaking again, sharing the conclusions she'd drawn throughout her short life with her mentor:
"Though I've lived for only a brief time, I've been surrounded by heroes—radiant beings like fixed stars. Even someone as inexperienced as me can learn truths from their life trajectories."
"You're right, teacher. To truly stand firm in this world, I need power—whether it's Rider, my kin, the current circumstances, or the support of heroes... All of these are immensely important to me. Of course, what you've given me is the most, and I've always been grateful for this kindness."
"But teacher, gaining such power must come at a cost, right?"
"Becoming Rider's Master is why I threw myself into the Holy Grail War, fighting for victory and survival. To earn my kin's support, I liberated my fellow homunculi and strive for their sake. By signing a contract with the Yggdmillennia, we homunculi cannot leave the battlefield yet and must assist them until the very end..."
Sakatsuki suddenly raised his hand, cutting off Sieg's words. "But the heroes' support is unconditional. That's just the kind of people they are—generous with their aid, never demanding anything in return."
"True. You are all that radiant," Sieg nodded, unbothered that this countered his own argument. "But whether it's a cost or an influence—I'm advancing forward with them as my goal."
Sakatsuki fell silent, then sighed. "I see. Though born of magecraft, you've broken free from the shackles of magi and are walking an even harder path... It seems pulling you away from the Black Faction will be difficult. After all, heroes do not betray."
"...I'm sorry, teacher." Sieg paused but mustered his courage. "But for me, pulling the trigger like shooting at some unknown target without even knowing what you intend to do—that's something I simply cannot do."
"Then I'll tell you. My wish is to save the world," Sakatsuki said with a mocking tone. "Well? With such a lofty wish, can I borrow your strength?"
Sieg fell silent again. The innocent homunculus had yet to learn lies or pretense. After earnest contemplation, she handed Sakatsuki the answer from her heart.
"But if the right to save humanity lies in the hands of a single person, wouldn't that be selection rather than salvation?"
This time, it was Sakatsuki's turn to go quiet. He held his teacup in silence before finally smiling faintly and standing up.
"Now I'm the one who seems hypocritical. Very well, let me rephrase my wish—I will reverse the end of a dying world and save humanity. And this... has nothing to do with any of you."
I will destroy you, and it has nothing to do with you.
The reverse holds true as well.
"...This will be a lonely battle, teacher," Sieg murmured after a moment.
In response, Sakatsuki showed the first genuine smile since entering the room.
"Just as I once told you: Always like this."
Though the smile was filled with madness, Sieg couldn't shake a pang of sorrow. She was about to speak, but Sakatsuki had already risen.
"I've received your graduation thesis, my dear student. You've graduated from my hands. Strive onward toward the stars, Sieg—may the light of us heroes forever illuminate your journey."
After uttering his farewell blessing, Sakatsuki stood up. Just then, the door burst open as a pink-haired paladin with a ponytail rushed in.
"Master, Master Master Master! Listen, I'm taking a bath tonight!"
The solemn atmosphere was instantly shattered. Sieg stared at the mud-covered Astolfo who looked like he'd been rolling in dirt, before finally squeezing out one word: "...Okay."
And so, the carefree Astolfo hummed a tune as he closed the bathroom door, leaving only Sakatsuki and Sieg staring at each other before sighing in unison.
"By the way, Sieg," Sakatsuki said, "there's one more thing. I'd like to borrow a few homunculi to assist with data recording. Don't worry, there's no life-threatening danger." Seeing Sieg's confused expression, he joked, "Consider it the 'price' for me teaching you."
"Mm-hmm." Sieg nodded shyly but agreed nonetheless. "I'll talk to Dürr (Leader of the homunculi). Just bring them back by tomorrow."
"Rest assured, we'll finish tonight."
Sakatsuki was about to say more when another knock came at the door, accompanied by a girl's voice.
"Is Sieg there? At Mr. Gordes' request, I've brought practice materials for you~~"
That voice—was it Jeanne d'Arc?
The irritation from being interrupted vanished from his face instantly. When Sieg turned to look at Sakatsuki, he found his teacher had already opened the bathroom door and ducked inside without regard for the occupant, closing it behind him with a click.
"Teacher... why are you hiding?"
Sieg didn't understand, but since Sakatsuki had already made his move, he decided not to overthink it and went to open the door.
"Good evening, Ruler..."