"The Holy Sword Project?"
Rias nodded in response to Issei's question.
"Yes, Yumi is the sole survivor of that experiment."
It was after their club activities, just as everyone was preparing to leave.
Rias had called Kazuki, Issei, and Asia aside, saying she had something important to share. What followed was the revelation of Yumi Kiba's traumatic past.
Years ago, a secret project known as the Holy Sword Project had been undertaken within the ranks of Christianity. Its aim was to artificially create individuals capable of wielding the Holy Sword, Excalibur—a weapon of unparalleled power against devils.
The sword, however, was notoriously selective about its wielder, choosing only one suitable human every few decades, if at all.
Some within the Church grew impatient. They viewed the inactivity of such a powerful weapon as wasteful and devised a plan to forcibly implant the "Holy Sword Wielder Gene" into children deemed to have potential. Their hope was to mass-produce individuals compatible with Excalibur.
The experiment failed miserably. None of the children adapted to the Holy Sword, and all were deemed "defective" and summarily executed—or so it was thought.
Yumi Kiba was the sole exception.
She had barely escaped being disposed of, aided by her fellow test subjects, who gave their lives to help her flee. Left critically wounded, she was eventually found and saved by Rias.
Rias had reincarnated Yumi as a devil, not out of a desire to bolster her peerage but to give her a second chance, a life free from the torment inflicted upon her by the Holy Sword and the Church.
Though initially consumed by hatred for both the Holy Sword and all associated with the Church, Yumi gradually mellowed under Rias's guidance.
She even began to smile, though it was clear her rage had merely been suppressed, not extinguished.
That fragile lid had now been torn open.
Yumi's desire for vengeance against Excalibur had been reignited, her emotions spiraling out of control.
The catalyst? A photograph.
Kazuki Fuwa couldn't help but feel anxious. He didn't blame himself, but there was no shaking the heavy sense of guilt.
The conversation ended, and Rias decided to send Issei and Asia home while Kazuki lingered.
"I'm sorry, Rias. There's no doubt that picture set her off," Kazuki admitted.
"It's not your fault," Rias replied softly. "But... Kazuki, does someone in your family have ties to the Church?"
"No, not really!! My mom was a devout Christian, but she passed away years ago. That photo was taken with my childhood friend and her father, who was a pastor. I don't even know where they are now."
"I see... Sorry for prying."
Kazuki gently placed a hand on Rias's shoulder.
"Don't worry about it… Still, I'm worried about Yumi."
Rias placed her hand over his, leaning into his touch.
"Me too..."
They stood together, gazing out the window as the rain continued to pour.
The following day brought an unexpected turn of events.
After school, Rias was summoned by Sona Sitri, the student council president, and brought Kazuki and Akeno with her to the student council room.
There, they were informed that two Holy Sword wielders dispatched by the Church had arrived in Kuoh Town. They had requested a formal negotiation with Rias, the devil overseeing the area.
The wielders had promised to visit the Occult Research Club room the following night under the condition that no hostilities would be initiated.
While the reason for the negotiation remained unclear, Rias had no choice but to comply.
She informed her peerage to be present for the meeting. However, complications arose sooner than expected.
That evening, one of the Holy Sword wielders showed up uninvited at Issei's house.
The wielder, it turned out, was Issei's childhood friend. She had taken the opportunity to drop by and greet his family, oblivious to the tensions her presence caused.
Issei's unsuspecting mother welcomed her warmly, inviting her in for tea and conversation.
Issei and his companions arrived home mid-visit, instantly recognizing her identity. Though both sides knew exactly who the other was, no conflict occurred.
The Church, it seemed, wished to avoid unnecessary confrontation before the negotiation, and Issei—knowing he was no match—wisely kept his temper in check.
After about thirty minutes of polite chatter, the visitor left. While Issei's mother remained delighted, Issei himself confessed he'd spent the entire time in a state of near panic.
Rias, upon hearing this, immediately teleported to Issei's house to check on him. Thankfully, both he and his family were unharmed.
Still, the revelation that Issei's childhood friend had become a Holy Sword wielder complicated matters.
Kazuki couldn't have predicted how this twist would come to haunt him as well in the days to come.
The following night, the entire Gremory peerage had gathered in the clubroom.
Rias and Akeno sat on the reception sofa, waiting for the two individuals they had been warned about. The atmosphere in the room was tense, almost suffocating.
For devils, Holy Sword wielders were the ultimate threat. Depending on the wielder, a single strike could mean utter annihilation.
The tension in the air wasn't just from the knowledge that such dangerous adversaries were about to enter their domain.
It was Yumi's presence that amplified the unease.
Yumi's eyes were locked onto the door, her entire body taut like a predator ready to strike.
She looked as though the moment the wielders stepped through that door, she'd lunge at them without hesitation and fuck them up.
Kazuki exchanged a glance with Issei and Koneko, silently agreeing they would intervene if Yumi lost control.
Eventually, ~KNOCK… KNOCK~ there was a knock at the door.
"Come in," Rias called out.
The door opened, and Sona Sitri stepped inside.
"Rias, I've brought your guests."
"Thank you, Sona!! Please, come in."
At Rias's cue, Sona gestured for the two individuals outside to enter.
The ones who stepped in were two girls, both appearing to be around the same age as Kazuki and the others.
The first had short blue hair with a green highlight streaking through her bangs, her sharp eyes giving her an intimidating presence.
The second had chestnut-colored hair styled into twin tails and wore a friendly smile that seemed oddly disarming. Both were undeniably beautiful, easily matching the girls already present in the room.
Kazuki immediately guessed that the twin-tailed girl must be Issei's childhood friend.
Yet, there was something about her face that struck a chord with him, as if he had seen her before.
While he struggled to place where, the twin-tailed girl stepped forward and spoke.
"Thank you for agreeing to meet with us tonight. I am Irina Shidou, and this is my partner, Xenovia. We are warriors serving the Church."
Kazuki's eyes widened as he focused on Irina's face. While her features had matured, there was something unmistakably familiar about her. His breath caught as he realized the truth.
"Irina?"
The name escaped Kazuki's lips before he could stop himself.
All eyes turned to him. Irina looked at him, puzzled by the sudden familiarity, while Xenovia's sharp gaze turned into a glare.
"Kazuki, is something wrong?" Rias asked, her voice calm but curious.
"Ah, no, it's just…" Kazuki faltered, unsure how to explain.
Before he could form a coherent response, Irina's eyes widened in recognition.
"Kazuki? Wait… could it be? Kazuki-nii?"
Her voice was filled with disbelief, and when their gazes locked, the certainty struck them both.
"It's really you, Irina!"
"No way! Kazuki-nii, it's really you!?"
Before he realized what was happening, Irina had dashed across the room and thrown herself into his arms.
"I've missed you so much, Kazuki-nii!"
Kazuki instinctively wrapped his arms around her. The sweet, fresh scent of her hair filled his senses, a far cry from the carefree child she used to be.
Now she was a fully grown woman, her toned yet undeniably feminine body pressing against him.
"It's been too long, Irina!!! I've missed you too."
"Wait, you're back in Kuoh Town? I thought you moved away!"
"I did," Kazuki explained as he gently pulled back, still holding her shoulders.
"After you moved to England, my dad got transferred, so we left too. But I came back here for high school."
"You should have told me sooner!" she pouted.
"Hey, don't blame me! I didn't even know where you were!"
"Hmm, I guess that's true… How are Uncle and Auntie? Are they doing well?"
Kazuki's expression darkened. "Irina… Mom and Dad passed away eight years ago. A car accident. I'm sorry I didn't tell you sooner."
"What? No… That can't be…" Irina's voice trembled, her cheerful demeanor cracking as she stared at him in disbelief.
"It's okay," Kazuki reassured her softly. "I was taken in by my grandfather after that, and he looked after me. Like I said, I came back to this town for high school, so I'm doing fine now."
Irina's expression shifted, a mix of sorrow and determination crossing her face. "Kazuki-nii… I had no idea. I'm so sorry for not being there for you."
"You don't need to apologize, Irina. It's been eight years… time has passed," Kazuki replied, though his tone betrayed a quiet ache.
"That's bullshit, Kazuki-nii! No matter how much time passes, losing someone you love never stops hurting! Uncle and Auntie… they treated me like their own daughter. They were so kind… so warm… I loved them," Irina said, tears forming in her eyes as memories of the past hit her.
"Irina… You're crying for my parents?" Kazuki asked, his heart tightening at the sight of her genuine sorrow.
"Yes, and for you too! I bet you didn't even let yourself cry back then, did you? You didn't want to worry Auntie and Uncle…"
"…Irina…" Kazuki whispered, her words striking him deeper than he expected. "Thank you…"
Before the moment could deepen, a chorus of exaggerated throat-clearing echoed through the room.
"Ahem!"
Kazuki and Irina turned to find the entire peerage glaring at them with varying degrees of irritation, save for Asia, who was blushing furiously. Rias's crimson gaze bore into Kazuki as she tapped her nails against her armrest.
"…So? Would you care to explain this little display of affection, Kazuki?" she asked, her voice laced with icy irritation.
"Ah, well, Irina is—"
"Hold on!! When exactly do you plan to stop clinging to each other like that?" Rias interrupted sharply, her ruby eyes narrowing dangerously.
"…Oh!" Kazuki and Irina yelped in unison, realizing they were still wrapped around each other.
Their embrace, which had started as a tearful reunion, now felt scandalously intimate.
"S-Sorry, Irina," Kazuki said, reluctantly letting her go.
"N-No, it's my fault, Kazuki-nii," Irina stammered, stepping back with flushed cheeks.
The sight of her—still stunningly beautiful yet adorably shy—made Kazuki's heart race.
"KAZUKI!"
"Y-Yes, Rias!?" he yelped, feeling the weight of her glare.
"You too, Irina. Compose yourself! Or have you forgotten he's already a devil?" Xenovia added, her sharp voice snapping at her partner.
"…A devil?" Irina froze, her wide eyes darting between Kazuki and Xenovia.
"Kazuki-nii, is that true? Are you really… a devil now?"
"…Yeah," Kazuki admitted, his voice steady despite the pain in her expression.
"Why…? Why would you become something like that?" Irina asked, clinging to him as if trying to shake the truth out of him.
"Listen, Irina," Kazuki began, gripping her wrists gently but firmly. "I was attacked by a fallen angel. I was seconds away from dying. Rias saved me by reincarnating me as a devil. If she hadn't, I wouldn't be standing here right now. I owe her my life. I don't regret it, and I won't apologize for surviving."
"I… I see," Irina whispered, her knees buckling as she collapsed to the floor, her hands covering her face in despair.
"This is too much… Not just Issei-kun but even Kazuki-nii has fallen and become a devil—"
"Pull yourself together, Irina!" Xenovia yapped, stepping forward with a commanding presence.
"I don't know what kind of relationship you have with him, but remember your duty as a warrior of God!"
"Y-You're right. I have my faith in God!" Irina responded, her eyes lighting up with determination.
"That's the spirit! God is always watching over us! Come, let us pray together, Irina!" Xenovia declared with an almost theatrical fervor.
"Yes, Xenovia!"
Together, the two clasped their hands and began praying aloud.
"Oh, Lord…!"
Kazuki watched the scene with a mix of bemusement and confusion. 'Was Irina always this extreme…?'
"Now then," Rias interjected, her tone sharp as her crimson gaze narrowed on Kazuki. "What exactly is your relationship with that girl, Kazuki?"
"Ah, she's… my childhood friend," Kazuki replied, scratching the back of his head awkwardly. "The kid in that old photo I showed you before? That's her."
"…WHATTTT!?"
The entire peerage, save for Rias, gasped in unison.