Chapter 427 Demon King Colosseum
Edited by: Kanaa-senpai
As Leohart finished explaining, Naruse Mio nodded along, her small head bobbing repeatedly.
”You went through all this trouble,” she said, “just to drag us into some alternate-space arena?”
Not only Naruse Mio, but Shela and Lucia were equally baffled—Leohart and his people couldn’t fathom what Curia was thinking either.
The so-called Colosseum was an alternate space left over from ancient times. This space didn’t manifest ordinarily; it required special methods to activate. Entering required one condition: you had to carry Demon King blood—impure was acceptable, but presence was mandatory.
The “Demon King blood” in question referred specifically to the lineage that once ruled this territory—in other words, Wilbert’s ancestral bloodline.
It was precisely because of this that, after Wilbert’s death, no matter how much Curia’s old fossils resented it, they had no choice but to watch Leohart—who appeared out of nowhere yet carried the Demon King’s blood—take the throne.
This alternate-space Colosseum was a creation left behind by a former Demon King. Its sole purpose: to prevent the family from descending into civil war over the succession to the Demon King’s position.
Only Devils possessing Demon King blood could enter—and once inside, leaving required killing your opponent. No matter how the succession struggle played out, when only one qualified candidate remained, there was naturally no reason for internal strife.
But as time passed and eras changed, the once-thriving family had steadily declined. The Colosseum hadn’t been activated for a very long time. Moreover, even if multiple young Devils of the same generation qualified for succession, they didn’t always escalate to the point where death matches were necessary. In most cases, the majority would rally behind the most outstanding candidate, and the others, seeing no hope, would simply withdraw and settle for their Peerage positions.
Due to the butterfly’s wing-beats scattering chaos, Aki wasn’t sure what methods Curia would use—but it seemed those old fossils had only this much in their arsenal. Ultimately, it was the same tired routine.
On the surface, this was about forcing a complete confrontation between Leohart and Naruse Mio—one of them had to die.
In reality, Curia planned to exploit Leohart’s confinement in the Colosseum, using the spiritual power at her disposal to eliminate his supporters and military forces entirely.
Much was missing compared to Aki’s memories—things like the Rating Game, which had been a massive spectacle with announcers and audiences rather than a simple arena fight, and Wilbert’s old subordinates’ allegiance ceremonies. But in the end, Curia had chosen the scorched-earth approach.
Naruse Mio naturally wouldn’t cooperate by offering her head on a platter. No matter how accommodating she was, there were limits—and Leohart didn’t have the nerve to ask. If he dared suggest it, she thought, he’d be the one dying.
Aki’s Origin Blood, after all, contained a portion provided by Naruse Mio. Even if that alternate space refused to acknowledge it, that wouldn’t stop him from forcibly breaching it.
According to Leohart’s proposal, he hoped that once the Colosseum manifested, Naruse Mio simply wouldn’t enter—admit before the entire Demon King Castle’s residents that she was afraid, concede defeat. That way, at least the ritual would be observed. The masses might be dissatisfied—especially those anticipating a Demon King showdown—but no one could keep using this issue to stir up trouble.
The ideal was grand. Reality was harsh.
If everything went smoothly, Naruse Mio wouldn’t need to risk anything, and the matter would resolve cleanly. After all, a sixteen or seventeen-year-old high school girl who’d only entered the supernatural world half a year ago being afraid of battle and fleeing at the last moment—that was perfectly normal. With some post-event spin, she wouldn’t lose any face—she might even gain a reputation as someone wise enough to read the room.
On the other hand, Leohart had managed things reasonably well over the years. Not many people were truly enthusiastic about a teenage girl becoming Demon King, even if she was Wilbert’s biological daughter. If Naruse Mio was willing to play the role of a figurehead princess, everyone except Curia would be delighted.
Come to think of it, Maria also carried Wilbert’s blood. But because she leaned more toward Shela’s Succubus lineage—to the point of lacking even red hair—this young princess seemed conveniently overlooked.
That said, since Curia had proposed this method, she clearly had contingencies. The Colosseum wasn’t something Naruse Mio could simply choose not to enter. Once she went in, Leohart would inevitably be trapped. The closer their strengths, the longer he’d be confined.
Moreover, the more harmonious their relationship, the harder it would be for them to deliver a killing blow—which would further prolong Leohart’s imprisonment. So Curia refrained from interfering with Naruse Mio and Leohart’s interactions, even encouraging them.
If Naruse Mio and Leohart were both forced into the Colosseum… would they truly fight to the death?
Naruse Mio’s growth was swift, but she was still a distance away from Demon King-class. Without tapping the power sealed within her, she was no match for Leohart. At that point, would Leohart really hold back? Would he watch his loyal subordinates and countless innocent Devils die senselessly while he remained trapped, waiting for some external solution? And that solution might not even work—ultimately, one of them would have to die.
Everyone present understood this. But no one called it out. Leohart’s side deliberately played dumb; Aki’s side was confident, planning to turn the tables.
Leohart’s subtle scheming wasn’t worth Aki’s scrutiny. No one sits securely on the Demon King throne while being pure-hearted. Even Sirzechs was a ruthless, merciless figure—notorious for his battlefield prowess, and known for using his good looks to charm Greyfia, then an enemy general, into defecting.
If they truly entered the Colosseum, Leohart’s survival would depend on his own choices. Let alone the power sealed within Naruse Mio—with Aki by her side, Leohart wouldn’t have the slightest chance of harming her.
The spacious palace hall grew awkwardly silent. Faced with Naruse Mio’s confusion, Leohart had no answers.
After a long pause, under Aki’s prompting through the Soul Network, Naruse Mio finally nodded in agreement. Shela, who hadn’t yet formed a Contract and thus hadn’t received the message, showed a flicker of surprise upon seeing Naruse Mio agree. “Shouldn’t they discuss this back at the residence?” she wondered. “She agreed just like that?”
Still, she wasn’t a young girl. She quickly composed herself, concealing her thoughts beneath an adorable smile.
Leohart noticed this subtly—but precisely because of it, he grew more convinced. He simply assumed Naruse Mio was inexperienced and had rashly agreed on her own.
”Good. Then it’s settled,” Leohart said. “I’ll discuss the specifics with Curia and notify you when we’ve set a date.”
Afraid Naruse Mio might change her mind, Leohart quickly added: “In the meantime, enjoy the city—all your expenses are on me. Oh, and I have a vacant manor. You can stay there for now.”
”No need,” Shela answered first this time, worried Naruse Mio might agree again and end up under their direct watch—where escape would be impossible. “Lord Ramsus is reunited with his niece after so long—we’d like to spend more time at his place.”
Leohart didn’t insist, watching Shela lead Naruse Mio and Maria out of the Demon King’s Hall.
The moment they returned to the residence, without even greeting Ramsus, Shela hurried into a room, deployed her Barrier, and began questioning. Aki could only walk her through the insights he’d shared via the Soul Network.
”So that’s how it is…” Shela said, relaxing.
Shela relaxed, sitting on the bed, her pale little feet swinging unconsciously—adorably carefree. With Aki backing them, she stopped worrying about Naruse Mio and shifted her attention to something else entirely.
”Is the Soul Contract really that incredible?” the loli Succubus housewife couldn’t help asking. “I was standing right next to you, and I didn’t sense a single ripple.”
”Mm. It really is that incredible,” Aki replied.
Like the ability to transform into a black cat, the Soul Covenant had transformed the master-servant contract inherited from Shela’s lineage into something entirely new. The master-servant contract was fundamentally about binding—some versions were straightforward, with betrayal meaning death. Shela’s version, however, made betrayal trigger sexual heat instead. Being touched by anyone other than the Master would shatter the mind, reducing one to a pleasure-seeking husk1.
Aki’s Soul Contract, however, couldn’t be described as similar—it was fundamentally different.
”Mother, I told you before, but you didn’t believe me…” Lucia teased, watching her mother’s expression. “Now you can try it yourself.”
Beyond communication, the Soul Contract’s true power lay in enhancing Dual Cultivation’s effects at the spiritual level, as well as sharing life itself.
Honestly, Aki was somewhat reluctant to waste a precious slot on Shela—all his current Contract partners were virgin schoolgirls. There’s a saying: judge actions, not hearts—judging hearts leaves no saints2.
Noticing Shela’s interest, Aki took the initiative: “The next full moon is in a few days, and since we can’t go back anyway, I’ll form the Contract with you then, Aunt Shela. That way, even if we split up later, we’ll have better safety and real-time communication.”
After advancing to Mid-God, Aki’s Soul Contract slots had multiplied. Since he could only form a maximum of four per month, plenty of slots remained.
Shela said nothing—just let her pale feet swing a little faster, her red lips curving upward slightly. The already exquisite charm of her Succubus features was now touched with genuine happiness. She hadn’t said it aloud, but upon learning the truth, she’d always felt somewhat excluded from Aki’s trio. Now, she was finally fully part of the group.
Unlike Greyfia and Venelana—both beautiful housewives—Shela was a widow. As for the generation gap issue… setting aside the fact that Aki had no intention of raising children, even if she did bear his child, from the Succubus trio’s perspective, it wouldn’t matter. Compared to all that, what held Shela back more was her pride and dignity as an elder—which made her a bit shy. By this point, however, she’d conveniently chosen to overlook it.
—
Summary:
Leohart explains the Colosseum’s rules and Curia’s political maneuver to force a death match between him and Naruse Mio. Aki recognizes Curia’s true plan to eliminate Leohart’s supporters while he’s trapped inside. Naruse Mio agrees to the plan under Aki’s guidance through the Soul Network, while Shela remains uncertain about the decision. The group returns to Ramsus’s residence where Shela learns the full extent of Aki’s Soul Contract capabilities and reluctantly accepts an offer to form one herself.
—
Trivia:
The Colosseum requires Demon King blood from Wilbert’s lineage to enter, but Aki’s Origin Blood contains a portion from Naruse Mio, allowing forcible breaching.
Curia is deliberately allowing Naruse Mio and Leohart to interact because their harmony prolongs Leohart’s imprisonment.
Maria possesses Wilbert’s blood but leans toward Succubus lineage, lacks red hair, and is conveniently overlooked as a princess candidate.
Shela’s master-servant contract triggers sexual heat upon betrayal rather than death, unlike standard binding contracts.
The Soul Covenant transformed Shela’s contract into something fundamentally different, enhancing Dual Cultivation and enabling life-sharing.
Sirzechs used his appearance to charm Greyfia, an enemy general, into defecting, demonstrating his ruthless and calculating nature.
Aki recently advanced to Mid-God, granting additional Soul Contract slots beyond the maximum of four per month.
Shela felt excluded from Aki’s inner circle but gains acceptance through the impending Contract formation.
Shela is a widow, unlike Greyfia and Venelana who are married housewives.
The full moon ritual is required for forming a new Soul Contract, and the next one occurs in a few days.
—
Translation Notes:
Notes:
• Naruse Mio – A gifted 17-year-old and daughter of the late Demon King Wilbert, she is a defiant, tsundere high schooler with signature red twin ponytails. Aki’s loyal girlfriend, she carries her father’s legacy while navigating the Gremory peerage and political intrigue. Despite her naivety, she boldly rejects the throne and manipulation, relying on Aki’s guidance and their bond to survive the supernatural world.
• Leohart – The young, dark-skinned Demon King with purple magical tattoos and a penchant for combat-ready attire rules the Demon King Castle following Wilbert’s death. Possessing Wilbert’s bloodline, he governs reasonably despite being under the Curia’s thumb. Though struggling against ancient schemers, he remains strategically clever, balancing casual regality with blunt, commanding authority when threatened.
• Naruse – Mio Naruse is a fair-skinned, red-haired schoolgirl with a voluptuous build who serves as a Demon King heir and Bishop in Aki’s peerage. Protected by the Gremory household, this “Sister Flower” evolves from a hesitant tsundere into Aki’s devoted, polyamorous partner. She maintains deep, essential bonds with her sister Maria, friend Kurumi, and her adoptive parents, forming the core Naruse family.
• Mio – Mio Naruse is a fair-skinned, voluptuous Kuoh Academy student with red twin-tails. As the Demon King’s daughter and Maria’s sister, she is a powerful Bishop in Aki’s peerage, currently managing sealed abilities involving gravity and hellfire. A proud, envious tsundere, she shares a deep, intimate bond with Aki while her presence often invites scrutiny, including comparisons to figures like Chisato.
• Y – The first initial/part of the name Y Ddraig Goch.
• Curia – Demon King Castle elder. Proposed the Colosseum death match method as a political maneuver. Plans to exploit Leohart’s confinement to eliminate his supporters using spiritual power. Has contingencies to force Naruse Mio’s entry. Refrains from interfering with Naruse Mio and Leohart’s interactions, even encouraging them.
• Lucia – A tall, elegant, white-haired succubus maid with an icy demeanor, she defies her nature through abstinence. As Shela’s daughter and Maria’s sister, she possesses Wilbert’s blood but leans toward her succubus lineage. Often overlooked, this companion of Naruse Mio is a confidante to the family, secretly vulnerable, and deeply invested in Aki, absorbing his energy while grappling with her feelings.
• Shela – A petite, white-haired Succubus Queen with ram horns and violet eyes, she balances youthful looks with a mature, cunning personality. A survivor of the Three-Way War and intuitive teacher, she lives in Aki’s household as a devoted partner and mother to Mio, Lucia, and Maria. Though she once sought to pair Aki with her daughters, she now claims him, blending matronly grace with strategic protection.
• Wilbert – The deceased former Demon King was a pacifist who made peace with Heroes and restored his realm after the Great War. A mysterious benefactor to the Naruse orphanage, he ensured his daughter, Mio, was raised by kind parents in the Human World. His immense power, sought by others, sealed Mio’s abilities. He was the ancestor of the ruling family, leaving behind his sister Sephie, lover Shela, and allies.
• Aki – A tall, handsome Kuoh Academy student and Red Dragon Emperor, he is a reincarnated cultivator who currently inhabits a pitch-black cat form with piercing azure eyes. Calculating and protective, he commands the Boosted Gear and Origin Blood. Connected to the Gremory household and Naruse Mio via a Soul Network, he manages a vast harem while navigating ancient conspiracies and his own feline instincts.
• Maria – A clever, headstrong succubus and royal subordinate, she is the daughter of Shela and possesses Wilbert’s blood. Though often overlooked as a princess candidate, she supports Aki’s romantic pursuits and teases him about Grayfia. She protects allies like Mio using her shapeshifting abilities—alternating between a playful loli form with amethyst eyes and a voluptuous figure—and gains power through dual cultivation.
• Sirzechs – Sirzechs Gremory, the red-haired Demon King Lucifer, is a formidable strategist and Rias’s brother. Known for his battlefield prowess, he charmed the enemy general Grayfia into defecting, later marrying her and fathering Georgix. A complex, often elusive leader, he balances diplomatic duties and rebuilding the Underworld with a cultivation obsession that frequently strains his family life, yet he remains an ally to Aki.
• Greyfia – As the Gremory household’s silver-haired Head Maid and Sirzechs’ devoted wife, she is a reserved beauty who balances domestic duties with her formidable Lucifugus bloodline and space mastery. Once an enemy general charmed into defection by Sirzechs, she is now his loyal partner and Venelana’s daughter-in-law. Beyond her marriage, she shares a deep, personal connection as the lover of Aki.
• Ramsus – A red-haired Peerage devil wearing round gold-rimmed glasses and formalwear. As an estate owner and uncle to his niece, Naruse Mio, he hosts her, Shela, and Maria at his villa. A cautious former subordinate of Sirzechs, he balances his role as a noble protector with administrative duties, including planning logistics with Demon King Leohart and observing Mio’s composure with newfound respect.
• Venelana – Venelana Gremory, the elegant, silver-haired matriarch of House Gremory and former Bael noble, is a refined beauty known for her powerful bloodline. Wife to Georg and mother to Rias and Sirzechs, she is often compared to figures like Shela and Greyfia. Despite her poised exterior and complex family status, she is currently involved in a secret affair with Aki, a reality likely known to Rias.
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Edited by Kanaa-senpai.
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