The night was silent, save for the rhythmic pounding of my heart. Rias stood atop the rooftop, bathed in the moon's silver glow, her gaze locked onto mine. I could feel her curiosity—her suspicion—weighing down on me like an unseen force.
She had seen everything.
The way I fought.The way my swords moved on their own.The way I evolved in the middle of battle.
I knew Rias Gremory. She was sharp, intelligent, and above all, protective of her peerage. If she sensed something unnatural about me, she wouldn't let it slide.
I met her gaze, keeping my expression calm. "Buchou."
She stepped off the rooftop, descending gracefully to the ground. Even now, she carried herself with an air of nobility, her crimson hair flowing like fire behind her.
"That was quite the display, Yuuto." Her tone was even, but I could hear the underlying intrigue. "I wasn't aware that you had mastered such techniques."
I kept my posture relaxed. "I've been training."
Her eyes flickered to the remnants of the battle—the faint scorch marks from the exorcist's holy energy, the disturbed earth from our clash. "Training alone wouldn't explain what I just witnessed."
Damn. She wasn't going to make this easy.
I weighed my options. Lying outright wasn't a good idea—Rias wasn't someone you could deceive easily. But telling the full truth? No way. I wasn't ready to reveal the Ability Mutation System just yet.
So I went with a half-truth.
"I've felt… different, lately," I admitted, glancing down at my hand. "Ever since our last battle against the fallen angels, something inside me has been changing. My abilities feel more fluid, like they're adapting on their own."
That wasn't technically a lie.
Rias studied me for a moment, her eyes searching for any hint of deception. Then, to my surprise, she smiled.
"I see."
I raised an eyebrow. "That's it?"
She chuckled. "You're not the only one who changes, Yuuto. Issei, Akeno, even Koneko—we're all growing stronger in our own ways. But yours… is rather unique."
She turned slightly, her gaze drifting to the stars. "Power that evolves in the middle of battle… it's almost like a Sacred Gear."
I tensed slightly.
She wasn't entirely wrong. Kiba never had a Sacred Gear in the original timeline—his power came purely from his demonic heritage and training. But my mutation system acted similarly to a Balance Breaker—a power that grew stronger over time, adapting to my needs.
Author's Note: Let's say this is an AU where Kiba didn't have Sacred Gear in the "Original" of the Protagonist's World. Yes, I know there are many inconsistencies and gaps, but the AI did it that way and I'm too lazy to correct it.
I needed to steer the conversation away before she dug deeper.
"I don't think it's a Sacred Gear," I said casually. "If it was, I imagine Azazel would've made a fuss about it by now."
Rias hummed in thought. "Perhaps." Then she turned back to me, her expression softening. "Regardless, I won't push you for answers. But, Yuuto…"
She stepped closer, her blue eyes serious.
"You're a part of my peerage. If anything is wrong—if this power ever feels unstable—I want you to tell me."
I nodded. "Of course, Buchou."
It was the answer she wanted to hear. And for now, it was enough.
The next day, I arrived at the Occult Research Clubroom, only to find Issei in the middle of one of his usual perverted rants.
"Buchou! Akeno-san! Let me serve you both tea so I can admire your beauty up close!" Issei declared dramatically, holding a tray in his hands. "I swear, I'll be the most devoted servant ever!"
Akeno giggled behind her hand. "Ara~ how bold of you, Issei-kun."
Rias sighed. "Just put the tea down before you drop it."
I took my usual seat, shaking my head in amusement. Despite the danger and chaos in this world, there were still moments like these—ridiculous, stupid, but strangely comforting.
Koneko, sitting across from me, nibbled on a cookie while watching Issei with a deadpan stare. "Idiot."
"H-Hey, that's harsh, Koneko-chan!" Issei whined.
I smirked. "She's just stating facts."
Before Issei could retaliate, the clubroom door suddenly burst open.
SLAM!
"Rias!"
A familiar voice rang through the room as Sona Sitri, the Student Council President and heir to the Sitri Clan, walked in. Behind her was her Queen, Tsubaki Shinra, her sharp gaze scanning the room.
Rias stood, her expression shifting to mild surprise. "Sona? What brings you here?"
Sona adjusted her glasses, her usually calm demeanor slightly tense. "We have a situation."
Everyone in the room immediately focused. If Sona was worried, that meant trouble.
"What happened?" Rias asked.
Sona sighed. "Last night, one of my patrol teams encountered a rogue faction of exorcists near Kuoh's borders."
I stiffened slightly. So it wasn't just the stray I fought—there were more of them.
Sona continued, "They were carrying holy weapons—not just basic light blades, but real Excalibur fragments."
A heavy silence fell over the room.
Excalibur fragments.
I knew what that meant.
The Excalibur Arc was fast approaching—the conflict between the Church, rogue exorcists, and Kuoh's devils over the stolen holy swords. Originally, Kiba would have gone rogue, driven by his vengeance against the Church for the Holy Sword Project.
But I wasn't that Kiba anymore.
If the Excaliburs were appearing early, that meant I needed to act fast.
Issei, of course, was the first to break the silence. "W-Wait, does that mean there are crazy sword-wielding priests running around the city?!"
"Yes," Sona confirmed. "And they aren't just low-ranked exorcists. We've identified at least one wielder of an Excalibur fragment among them."
That narrowed it down.
In the original story, the wielder of the Excalibur Rapidly fragment was Xenovia Quarta, a powerful exorcist from the Church. She, along with Irina Shidou, was sent to Kuoh to recover the stolen Excaliburs.
But if the timeline was already changing…
Could it be someone else?
Rias crossed her arms. "We can't allow holy swords to run unchecked in our territory. Sona, do you need our assistance?"
Sona nodded. "Yes. We should work together to deal with this threat before it escalates."
Rias turned to us. "Everyone, we'll begin investigating immediately."
Issei gulped. "W-Wait, does this mean we have to fight against holy swords? Isn't that, like, super deadly for devils?"
"Only if you let yourself get hit," I said, standing. "And trust me, you don't want to."
I could feel my Abyssal Armory humming in anticipation. If there were Excalibur fragments involved, then my swords were about to get another upgrade.
And I wasn't about to let this opportunity slip away.