Devils were one of the races that made up the Three Factions, standing alongside Angels and Fallen Angels. Three forces that had existed since time immemorial, back when the Original Lucifer still ruled the Underworld.
The social structure of devils revolved around the 72 Pillars, the noble families that formed the backbone of demonic aristocracy. Each of them possessed vast territories, private armies, and unique hereditary abilities.
There were also the so-called Extra Devils, families that didn't belong to the original Pillars but had earned recognition and noble status after demonstrating their power and merit during the Great War. The Lucifuge Clan, from which Grayfia hailed, was one of them.
But after the Civil War, the balance of power changed. The old noble houses had been weakened, and many were wiped out during the Great War, forcing the new Maous to rebuild everything from the ground up.
Among those Maous was Ajuka Beelzebub, one of the Four Great Maous and the eccentric genius who created one of the greatest inventions in demonic history: the Evil Pieces.
A brilliant method for transforming humans and other races into reincarnated devils.
It was a process that not only granted new life but also altered the individual's entire spiritual structure, turning them into a true devil, even if they weren't of pure blood.
To Keiji, that sounded a lot like Aizen's Hollowfication experiment with the former Captains and Lieutenants of the Gotei 13.
'Did both of them have the same goal?'
Perhaps their motives were different, but the essence was the same. Granting one's body the traits of another "race".
Through the Evil Pieces, reincarnated devils could gain part of the natural abilities possessed by pure-blooded devils: enhanced physical prowess and demonic power capable of creating supernatural phenomena known as magic.
If the Evil Pieces could do that… was Aizen trying to achieve something similar with Hollowfication?
Combining both Hollow and Shinigami traits to forge a new kind of spiritual structure... something that surpassed the "natural level" of either race.
Sora's voice echoed in Keiji's mind.
{To create a hybrid soul, strong enough to break past the natural limits of a Shinigami.}
'Makes sense…'
A mere technique or new ability alone could never change a Captain's level of power. But if you mix both the characteristics of a Hollow and a Shinigami to strengthen the essence of the soul... your potential could rise exponentially.
'Maybe that's it… a path to surpass the limit.'
Keiji knew that limit all too well. Even though he could currently reach Spiritual Class 1 artificially through his Shikai, he could still feel the invisible "barrier" that prevented him from going further.
No matter how much reishi he absorbed to strengthen his spiritual body, there always came a point where it began to "swell", as if the structure of his soul could no longer withstand the sheer density of energy.
That was the "limit" of a Shinigami.
'Unless…'
{Unless you change the very structure of your soul.}
Just like Aizen had attempted with his experiment. Or like Ajuka Beelzebub had done with the Evil Pieces.
The same principle in two different worlds — changing the nature of one's being.
[——]
Grayfia walked ahead with her flawless posture, her footsteps echoing softly through the hallways that led them to the old elegant building, now renovated to serve as the façade of the Occult Research Club.
She could have easily arrived there using teleportation magic, but Keiji's insistence on "experiencing" her world firsthand had made them walk the entire way…
When the dark wooden door opened with a soft click, the room revealed a spacious parlor, lit by colorful stained glass windows and a warm fireplace crackling at the far end.
Rias Gremory was seated in a velvet armchair, with Akeno to her right serving tea on a porcelain tray, and Koneko quietly munching on cookies from a chair in the corner.
Grayfia entered first, giving a polite bow, followed by Aizawa and finally Keiji, who looked completely at ease.
Rias stood as soon as she saw them, elegantly adjusting her long red hair.
"Welcome."
Akeno gave a short bow, her smile widening slightly at the sight of their visitors. Koneko, on the other hand, only glanced up from her cookies for a few seconds before going right back to eating.
Keiji looked at the trio, his eyes wandering lazily between the three girls before settling on Rias.
"So you're the girl I'm supposed to marry?"
Rias blinked a few times, surprised by his complete lack of formality, but nodded nonetheless.
"I'm Rias Gremory, heiress of the Gremory Clan. It's a pleasure to meet you."
She studied him carefully, trying to keep her composure even though her curiosity was plain to see. After a short silence, she frowned slightly.
"If I may ask… what exactly are you? Your friend seems human, but you feel… different."
Keiji raised an eyebrow. He was wearing normal clothes, so he shouldn't have looked any different from a human. But just as he could sense a person's soul through their reiatsu, it seemed that Rias — and perhaps all devils — had a way to perceive that same distinction.
"I'm Ayano Keiji, a Shinigami."
The word hung in the air for a moment until Akeno tilted her head, intrigued.
"Shinigami? Like the servants of Lord Hades in the Underworld?"
Keiji turned toward Grayfia, narrowing his eyes.
"You've got Shinigami here and didn't tell me?"
Now he was actually curious to meet these "colleagues".
Grayfia cleared her throat delicately, her expression perfectly composed.
"Let's stay focused on the main point, Keiji-san."
Her tone carried a hint of emphasis before she turned to Rias.
"Rias-ojousama, this is the man I mentioned. The one who can help you with your engagement problem regarding Riser Phenex."
Rias straightened, already suspecting that was the reason for their visit.
"Him?"
She couldn't quite tell if Keiji was strong or not, but if Grayfia trusted him, then Rias had no reason to doubt her.
After all, Grayfia was called the Strongest Queen for a reason.
And even though Rias had never met a Shinigami in person before, she'd learned that most were said to rival High-Class Devils in power.
Grayfia confirmed with a small nod.
"The idea is simple. Keiji-san will act as a rival suitor, someone who's fallen in love with Rias-ojousama. He'll challenge Riser Phenex to a Rating Game, and if he wins, the marriage contract will be nullified."
Akeno let out a light laugh, resting her chin in her hand.
"So basically… Buchou will just be trading one fiancé for another?"
Keiji smirked slightly and shrugged.
"More or less, but don't worry. I have absolutely no intention of getting married, if that makes you feel any better."
Rias glanced at him sideways, unsure whether to laugh or sigh. Grayfia reacted the same but decided not to correct his laid-back attitude.
"And if I agree to this… how much time would that give me?"
"As much as you want. Of course, if you ever meet someone you actually want to marry, you can just ignore me and move on."
His answer was simple, almost too casual, but that was exactly how Keiji was. After all, this was nothing more than a mission issued by Grayfia, and he was only there for the reward.
Marry Rias? Please… she didn't seem like his type at all.
Akeno rested her chin on her hand, watching from the side with a playful smile.
"Hm… but won't that leave Buchou's image a little… tarnished, don't you think?"
Her narrow eyes turned toward Rias, gleaming with teasing amusement.
"After all, two canceled engagements in a row... the Underworld is going to love talking about that~"
Grayfia kept her expression composed.
"That is an unavoidable risk. Rias-ojousama will have to deal with the consequences later. For now, the focus is on preventing the marriage with Riser Phenex."
Before Rias could share her thoughts, Keiji interrupted, his relaxed gaze shifting between the three girls.
"That's easy to fix."
Rias blinked, confused.
"What do you mean?"
Keiji slipped his hands into his pockets and answered in a calm, almost detached tone.
"Just get stronger. No matter where you go, power is the only thing that matters. If you're strong enough, no one will care how many engagements you've broken off, Gremory-san."
Rias fell silent for a few seconds, processing his words. His logic was blunt and a little harsh, but there was truth in it. In the Underworld — just like anywhere else — power and influence ruled everything.
Finally, she took a deep breath and lifted her eyes.
"Alright. If he's really capable of defeating Riser, then I'll trust you, Grayfia."
Grayfia nodded, satisfied with the answer, and bowed slightly.
"Understood, Ojou-sama."
At that moment, the clubroom door creaked open, and three figures stepped inside. Hyoudou Issei, wearing a confused and curious expression; Kiba Yuuto, polite as always with his calm smile; and Asia Argento, timidly walking a few steps behind the two.
Kiba was the first to notice the guests. His eyes shifted between Grayfia, Keiji, and Aizawa before he muttered quietly,
"Oh my…"
Rias sighed, running a hand through her hair as she looked over each of her servants.
"Looks like everyone's here. Before we start the club activities, there's something I need to tell all of you."
Grayfia took a step forward.
"Ojou-sama, would you like me to explain the situation?"
Rias waved her hand gently to decline the offer. She took a deep breath, preparing to begin.
"The truth is—"
But before she could continue, the floor beneath them began to glow. A magic circle spread across the room, expanding rapidly under everyone's feet. The crimson lines crisscrossed and danced, emitting a warm glow. The Gremory crest engraved in the center distorted and spun, transforming into a new symbol.
Kiba's eyes widened in recognition.
"That emblem… it's the Phenex family crest."
The glow intensified, and within seconds the heat rose sharply, making the curtains sway and the fireplace flame flicker. Then, a confident and melodic male voice echoed through the room, resonating like silk over glass.
"Fuu… it's been a long time since I visited the human world."
When the light finally faded, a tall, handsome man with golden hair stood in the center of the circle. He wore a perfectly tailored crimson suit and carried a smug, ever-present smile.
He spread his arms in a theatrical gesture, as if performing on a grand stage.
"My lovely Rias… I've come to see you."
Riser's voice was smooth and dripping with self-assurance, every syllable sounding like it expected applause.
Aizawa sighed beside Keiji, his half-lidded eyes filled with tired resignation.
"This is the fiancé?"
Keiji nodded slightly, glancing between Riser and Rias.
"Seems like it."
Judging power levels based on his own perception could be misleading, but Keiji didn't find Riser impressive in the slightest.
From the energy he emitted… the guy was actually weak.
'Grayfia-san was right to call him a "speck of dust".'
Beside him, Rias clenched her fists, her eyes hardening the moment she saw Riser.
"Now, Rias. Let's go take a look at the ceremony hall. The date's already been set, so we need to check it before then."
Riser spoke with a tone that tried to sound gentlemanly, but came off possessive instead.
"... Let go of me, Riser."
Rias snapped back as she pulled away from his outstretched hand, her own demonic power beginning to flare around her.
But before the argument could escalate, Keiji exchanged a brief glance with Grayfia and stepped forward, crossing the room with calm steps, completely at ease under the watchful eyes of Rias' servants.
"So this is Phenex-san? There's something I wanted to discuss with you."
"Oh? And who are you supposed to be?"
Riser's voice dripped with irritation.
"You don't look like one of Rias's servants… and you're not a devil either. What are you?"
He asked, scanning Keiji as if assessing him and clearly finding nothing impressive.
"So you can tell too, huh?"
Apparently, it was something all devils — or rather, all supernatural beings in this world — could sense. Probably the same way Keiji could read someone's essence through their reiatsu.
"I'm Ayano Keiji… and Gremory-san and I are in love."
Keiji said it with the most idleness expression imaginable.
"... Is that so?"
Rias wanted to scream at him. To tell him to at least try to act convincing. Calling her "Rias" instead of "Gremory-san" would've helped a lot. But she took the chance anyway.
She stepped to his side and wrapped her arms around his, pressing her chest against him deliberately.
"That's right, Riser! Keiji is the man I chose to marry!"
Riser twitched as if his flaming pride had been insulted.
"... You know, Rias, I am also a devil who bears the name of the Phenex Clan. I cannot allow my family name to be disgraced. I didn't even want to come to a rundown old building like this in the human world. In fact, I despise this world. The fire and wind here are filthy. For a devil like me, who rules over fire and wind, I can't stand it!"
Flames erupted around Riser, forming fiery motes that floated and crackled through the room.
"Stop with this. I'll take you back to the Underworld, even if I have to burn all your servants and that fool who dared interfere."
Rias's servants exchanged uncertain looks, trying to decide what to do. Issei looked completely lost; Kiba adjusted his stance, readying his Sacred Gear; Akeno smiled faintly, her eyes narrowing in amusement; and Koneko stepped forward, her expression calm but alert.
Grayfia remained composed, her crimson eyes calmly calculating every movement, while Aizawa stood observing from the side, prepared to activate his Quirk and hoping it would actually work, anything to minimize the collateral damage.
Rias squeezed Keiji's arm tightly, pressing her head against his shoulder as if to make a public vow. The faint blush coloring her cheeks made it clear that she was serious, or at least wanted everyone to believe she was.
Keiji watched the flames dance around Riser and let out a comment that sounded almost absentminded.
"Burning people and spilling blood over family pride is a pretty outdated method, you know? But if that's how Phenex-san wants to preserve his family's honor, then we can settle this in a civilized way with a Rating Game, like you devils seem to enjoy."
Riser raised an eyebrow, looking both offended and dismissive of Keiji. The smug smile returned to his lips.
"And what makes you think I'd accept a challenge from some random nobody?"
The flames behind him flared, forming what looked like blazing wings. A dramatic phoenix display worthy of a stage show.
Keiji sighed quietly at the over-the-top performance.
Grayfia stepped forward, her composed demeanor shifting into the commanding presence of the Strongest Queen for just an instant.
"Please, calm yourself, Riser-sama. If you continue, I won't stay silent about it. For the honor of Sirzechs-sama, I won't hold back."
Keiji glanced sideways at her while Riser's expression turned serious at the sound of Grayfia's calm yet cutting voice. The flames surrounding his body dimmed, and he exhaled deeply, shaking his head.
"... To be told that by the "Strongest Queen", even I would be scared.... I definitely wouldn't want to fight the people from Sirzech-sama's group, which is known to be made up of monsters."
Keiji could also feel the cold, restrained power radiating from Grayfia, and it made him look at her with genuine interest.
'Grayfia-san is strong too~'
"Master and Sirzechs-sama both knew things would come to this. Everyone knew it wouldn't be resolved, so they decided to make a last resort."
"Last resort?"
"Riser-sama, why not settle this in a Rating Game against Keiji-san?"
Riser frowned, considering the consequences and his pride, but also considering the political advantage of resolving everything officially.
In truth, since this had the support of Sirzechs himself, Riser had no real choice but to accept. Even if he tried to argue, they would only come back with stronger reasons later.
That was the price of being under a Maou's gaze.
"Very well," Riser finally said. "If this is how we'll end things honorably, then I accept. But the rules will be clear, I will not take part in tricks or humiliations."
He looked from Grayfia, to Rias, and finally to Keiji.
"I accept your challenge."