Part I:
Morning sunlight streamed through the windows of Classroom 3-B as Caelan Lucifuge stood at the blackboard, writing out differential equations with mechanical precision.
"The derivative of f(x) = x³ + 2x² - 5x + 7 is—" He turned to face the class. "—anyone?"
Silence.
Half the students were asleep.
The other half were staring at him with glazed eyes.
"Hyoudou."
Issei jerked awake. "BOOBS—I MEAN WHAT?!"
The class snickered.
Caelan's expression didn't change. "The derivative. Now."
"Uh—uh—" Issei scrambled to look at his notes. "Three x squared plus four x minus five?"
"Correct. Try to stay awake."
"Yes, sensei!"
Caelan returned to the board.
At least he's learning. Slowly. Very slowly.
The bell rang, signalling the end of class.
"Homework is problems fifteen through thirty in your textbook. Dismissed."
Students filed out, most looking relieved to escape.
Issei lingered near the door. "Sensei? Can I ask you something?"
"You just did."
"I meant—another something."
"Make it quick."
"How do you deal with Gabriel-sensei?"
Caelan's pen paused mid-equation. "What?"
"She keeps showing up at your classroom. Everyone's noticed. And she's always smiling at you. And—"
"Hyoudou."
"Yes, sensei?"
"Mind your own business."
"But—"
"Go to your next class."
Issei wisely fled.
Leaving Caelan alone with his thoughts.
Gabriel has been... persistent.
Every lunch break. Every free period. Always finding excuses to discuss 'magical theory.
It's exhausting.
Get her.
NO.
As if summoned by his thoughts, there was a knock on the door.
"Lord Lucifuge~ Do you have a moment?"
Speak of the angel.
"I'm busy."
The door opened anyway.
Gabriel swept in, carrying her usual thermos and a box of what smelled like freshly baked cookies.
"I brought snacks!"
"I said I was busy."
"You're just grading papers. That's not busy~" She settled into the chair across from his desk. "Besides, I have a fascinating question about entropic manipulation that I simply must discuss with you."
Caelan sighed.
This was his life now.
Part II:
Meanwhile, in the gymnasium, Azazel was running what he called "Practical Gear Training."
What it actually was: organized chaos.
"BOOST!" Issei's Boosted Gear activated as he charged at a training dummy.
"Wrong!" Azazel called out from where he was lounging on the bleachers. "You're relying too much on raw power! Use strategy!"
"WHAT STRATEGY?! IT'S A DUMMY!"
"Pretend it's an enemy! Think! Where are its weak points?"
"IT DOESN'T HAVE WEAK POINTS! IT'S MADE OF WOOD!"
"Then MAKE weak points!" Azazel grinned. "Use your environment! The ceiling! The floor! Get creative!"
Issei looked at the ceiling.
Then at the floor.
Then back at Azazel.
"You want me to drop the ceiling on it?"
"Now you're thinking!"
"THAT'S INSANE!"
"That's TACTICS, kid!"
Nearby, Xenovia was sparring with Kiba, both moving at speeds that would make normal humans dizzy.
"Your form is improving," Kiba noted, parrying Durandal with a demonic sword.
"Azazel-sensei's been teaching me how to fight without relying solely on Durandal's power," Xenovia replied, pressing the attack. "Apparently I've been 'swinging like a barbarian.'"
"You said it, not me," Azazel called out.
"I HEARD THAT!"
"You were supposed to!"
Koneko, meanwhile, was punching a reinforced training dummy so hard it was denting.
Each hit made a sound like a small explosion.
"Good!" Azazel observed. "But you're still holding back! Use your Senjutsu!"
"Don't want to."
"Why not?"
"Personal reasons."
"Fair enough." Azazel shrugged. "But you're limiting yourself. Just saying."
Koneko ignored him and continued punching.
In the corner, Asia was practicing her healing magic on—
"SENPAI! HOLD STILL!"
"I'M TRYING! YOUR TWILIGHT HEALING TICKLES!"
"It's not supposed to tickle! You're just sensitive!"
"I'M NOT SENSITIVE! YOUR MAGIC IS WEIRD!"
Azazel watched this chaos unfold with a satisfied smile.
These kids are going to be monsters when they grow up. Actual, terrifying monsters.
I love it.
Part III:
After school, the entire Gremory peerage gathered in the Occult Research Club building.
Rias sat at her desk; Ravel perched on the armrest beside her.
The rest of the peerage was scattered around the room: Akeno making tea, Koneko eating cookies, Kiba politely standing near the window, Xenovia examining Durandal, Asia sitting nervously, and Issei sprawled on the couch.
And, unusually, Irina Shidou was also present—standing near the door in her white and gold angel attire, looking very official.
"Irina," Rias greeted warmly. "It's good to see you. Though I'm surprised you're here for a devil peerage meeting."
"Gabriel-sama asked me to accompany her to the meeting," Irina explained, then gestured to the door.
Gabriel swept in, still in her teacher's attire, smiling radiantly.
"Good afternoon, everyone!"
"Gabriel-sensei!" Asia immediately perked up. "Are you here to teach us more healing magic?"
"Not today, dear. I'm actually here as an observer. Michael-sama wanted me to maintain a presence at these meetings to strengthen inter-faction cooperation~"
Translation: Heaven was keeping an eye on devil activities.
Rias understood this but smiled graciously. "You're always welcome, Gabriel-sensei. Please, have a seat."
Gabriel settled onto the couch next to Issei, who immediately went rigid.
Angel. Sitting. Next. To. Me.
Don't be weird. Don't be weird. Don't—
"Issei-kun~" Gabriel smiled at him. "I've been meaning to ask—how is your training with the Boosted Gear progressing?"
"Uh—good! Really good! Azazel-sensei is teaching me strategies and—why are you so close?!"
Gabriel had leaned in, her face about six inches from his.
"Oh? Am I too close? I'm sorry~ I forget that devils have different personal space boundaries~"
"THAT'S NOT A DEVIL THING! THAT'S A HUMAN THING!"
Akeno giggled from across the room. "Ara ara~ Gabriel-sama is quite bold~"
"I'm just being friendly!"
"That's what they all say," Koneko muttered.
Rias cleared her throat. "Right. Well. Moving on. I have an important announcement."
Everyone turned to face her.
"Summer vacation starts next week. And I've decided that we'll be spending it in the Underworld."
"The Underworld?!" Issei sat up. "Like, actual Hell?!"
"It's not called Hell anymore, Issei. It's the Underworld. The realm of devils." Rias smiled. "I want to formally introduce you all to my family and give you a chance to experience devil society."
"I've been to the Underworld," Xenovia said. "When I was an exorcist. We were hunting stray devils."
"This will be different," Rias assured her. "You'll be my guest, not an enemy. You'll see the Underworld as it truly is—cities, culture, civilization."
"That sounds wonderful!" Asia clasped her hands together. "I've always wanted to see where you grew up, Rias-sama!"
"You'll love it," Ravel said confidently. "The Underworld is beautiful. Especially the Gremory territory."
"There's also going to be a Young Devils Gathering while we're there," Rias continued. "It's a social event where the heirs of the major families meet to discuss current events and politics."
"Politics." Issei groaned. "That sounds boring."
"It's important," Kiba said quietly. "After the Khaos Brigade attack, the noble families need to coordinate their response."
"Exactly," Rias nodded. "The gathering is being hosted by my cousin, Lucien Gremory."
At the mention of that name, Gabriel's eyes flicked toward the window.
Where, coincidentally, Caelan had just walked past the building with Hoarfrost.
Lucien Gremory. Caelan's twin brother. The 'golden child.' This will be... interesting.
"Will Caelan-sensei be attending?" Asia asked innocently.
"I doubt it," Rias said. "He avoids family gatherings. But—" She paused. "—my father did send him a formal invitation. So, there's a chance."
"A very small chance," Ravel added. "Like, one percent."
"Point-zero-one percent," Koneko corrected.
"He'll come," Gabriel said suddenly.
Everyone looked at her.
"What makes you so sure?" Rias asked.
Gabriel's smile was mysterious. "Call it intuition~"
Part IV:
That evening, Caelan sat in his office in the Eastern Marches, reviewing trade contracts, when a teleportation circle flared to life.
Not again.
But it wasn't Sirzechs.
It was Zeoticus Gremory.
His grandfather.
Caelan looked up, his expression immediately going cold. "You're trespassing."
"I'm visiting my grandson," Zeoticus replied calmly, settling into the chair across from Caelan's desk uninvited. "There's a difference."
"Not to me. Leave."
"Not until you hear me out."
"I don't want to hear—"
"There's a Young Devils Gathering in two weeks. In the Underworld. Your brother is hosting it."
Caelan's pen stopped moving.
"...And?"
"And I'm formally inviting you to attend. As the head of House Lucifuge, your presence would be... appropriate."
"I have no interest in noble gatherings."
"It's not just a social event. It's a strategic meeting." Zeoticus leaned forward. "After the Khaos Brigade attack, all the major families are on edge. They need to coordinate. Share intelligence. Plan defences. Your input would be valuable."
"Then they can read my written reports."
"Caelan—"
"I said no."
Zeoticus was quiet for a moment. Then he pulled out a sealed envelope. "Lucien asked me to give you this. Personally."
Caelan stared at the envelope like it might explode.
"I'm not reading that."
"It's from your brother."
"I don't have a brother."
"Caelan—"
"Legally, I'm a Lucifuge. Lucien is a Gremory. We're not related."
"You're twins."
"Genetically, yes. Practically, no." Caelan returned to his paperwork. "Tell Lucien I'm not interested in reconciliation. Or politics. Or family gatherings. I'm busy."
"With what?"
"Running a territory. Managing businesses. Living my life without Gremory's interfering in it."
Zeoticus sighed and set the envelope on the desk. "I'll leave this here. In case you change your mind."
He stood to leave.
Then paused at the door. "For what it's worth, Caelan—I'm proud of what you've accomplished. You've built something remarkable here. And I'm sorry we didn't appreciate that sooner."
He teleported away before Caelan could respond.
Leaving Caelan alone with the unopened letter.
He stared at it for a long moment.
Then shoved it into a drawer without reading it.
Want to read it?
Not interested.
But his eyes kept drifting back to the drawer.
Really?
...Damn it.
Part V:
One week later, the Gremory peerage gathered at the teleportation circle in the Occult Research Club building.
Rias stood at the center, already dressed in formal devil attire—a crimson and black dress that screamed 'nobility.'
Ravel wore something similar in gold and red.
The rest of the peerage was dressed more casually, though Akeno had chosen a rather revealing kimono that made Issei's brain short-circuit.
"Is everyone ready?" Rias asked.
"Ready!" Asia chirped.
"As ready as I'll ever be," Xenovia muttered, adjusting Durandal on her back.
"This is so exciting!" Ravel squeezed Rias's hand. "You're going to love the Underworld, everyone!"
"Will there be food?" Koneko asked.
"So much food," Ravel promised.
"I'm in."
Rias activated the teleportation circle.
Crimson light flared.
And the entire peerage vanished.
They reappeared in a massive entrance hall made of red stone and decorated with crimson banners bearing the Gremory family crest.
"Whoa," Issei breathed, looking around. "This place is HUGE."
"This is just the entrance hall," Rias said with a smile. "Wait until you see the rest of the estate."
"Welcome home, Rias-sama." A butler appeared from a side door, bowing deeply. "Lord Zeoticus and Lady Venelana are waiting in the main hall."
"Thank you, Sebastian. We'll head there now."
The peerage followed Rias through winding corridors lined with portraits of past Gremory family members.
Issei couldn't help but notice that one portrait—a young man with crimson hair and green eyes—looked remarkably like Rias.
"Who's that?" he whispered to Kiba.
"Sirzechs Lucifer. Rias's older brother."
"Oh. Right."
"Exactly."
They entered the main hall—a vast room with high ceilings, elegant furniture, and a massive fireplace.
Standing near the fireplace were two figures:
Zeoticus Gremory—tall, distinguished, with the same crimson hair as Rias, dressed in formal robes.
And Venelana Gremory—elegant, beautiful, with long brown hair and a warm smile, wearing a flowing gown.
"Mother! Father!" Rias immediately rushed forward.
"Rias!" Venelana embraced her daughter. "It's so good to see you! And you brought your peerage!"
"And your wife!" Zeoticus added, looking at Ravel with approval. "Welcome to the family, Ravel."
Ravel bowed politely. "Thank you for having me, Lord Gremory, Lady Gremory."
"Please, call us by our names. You're family now." Venelana smiled warmly, then turned to the rest of the group. "And you must be Rias's servants! Welcome!"
"Thank you for having us," Akeno said gracefully, bowing.
The others followed suit—except Issei, who was too busy staring at the opulence to remember his manners.
"You're the Red Dragon Emperor," Zeoticus observed, studying Issei. "Hyoudou Issei, correct?"
"Y-Yes, sir! That's me! The Oppai Dragon! I mean—the Red Dragon Emperor! Not the Oppai thing! That's just a nickname! A bad nickname! That I hate! Please forget I said that!"
Ddraig's voice rumbled from the Boosted Gear. [Partner. Stop embarrassing me.]
"I'M TRYING!"
Venelana laughed softly. "He's adorable."
"He's an idiot," Koneko said flatly.
"HEY!"
"But a loyal idiot," Kiba added diplomatically.
"THAT'S NOT BETTER!"
Zeoticus smiled. "Well, loyal or not, you're all welcome here. Please, make yourselves at home. Dinner will be served in two hours. Until then, feel free to explore the estate."
"Thank you, Father," Rias said.
As the peerage dispersed to explore, Venelana leaned over to her husband. "Do you think Caelan will come?"
"I don't know," Zeoticus admitted. "I gave him the invitation. But he didn't seem interested."
"He never does. But he always surprises us."
"That he does."
Part VI:
Later that evening, during dinner, the entire family gathered in the formal dining hall.
It was a massive table, easily seating twenty people.
Present were:
- Rias and her peerage
- Zeoticus and Venelana
- Ravel's family (Lord and Lady Phenex, who'd been invited as political courtesy)
- And several other minor Gremory family members
Noticeably absent: Sirzechs and Grayfia (too busy with Satan duties) and Caelan (who'd declined the invitation).
The conversation was polite, formal, and boring.
Until Venelana asked the question that had been on everyone's mind.
"Rias, dear. Have you seen Caelan recently?"
The table went quiet.
Rias carefully set down her fork. "I see him at school. He's my math teacher."
"How is he?"
"Cold. Professional. Brilliant." Rias smiled slightly. "He helped me with the Rating Game against Riser. And he protected everyone during the Khaos Brigade attack."
"That sounds like him," Zeoticus murmured. "Always helping from the shadows."
"He's also being aggressively pursued by Gabriel," Ravel added cheerfully.
Spit-take sounds from multiple people.
"He's WHAT?!" Venelana looked scandalized.
"The Archangel Gabriel. She's very interested in him. Romantically, I think. Or at least, she's working up to it." Ravel grinned. "It's actually quite entertaining to watch. He keeps trying to maintain professional distance, and she keeps finding excuses to be near him."
Lord Phenex chuckled. "An angel pursuing a devil. How... progressive."
"Grayfia is not happy about it," Zeoticus noted.
"Why?" Rias asked, confused.
"Because that's her son," Venelana said gently. "Even if they're estranged, she's still protective of him."
"Irrationally protective, from what I've heard," Lord Phenex added. "Apparently she nearly froze Gabriel into a wall last week when she saw them having tea together."
"That's... concerning," Rias said.
"That's Grayfia," Zeoticus said with a slight smile. "She doesn't do anything halfway. Including maternal instincts."
The conversation drifted to other topics, but Issei couldn't help but notice the sadness in Venelana's eyes when she talked about Caelan.
They really do miss him, Issei thought. Even if they won't admit it.
Part VII:
Two days later, the Young Devils Gathering was held at a neutral venue—a massive conference hall in the center of the Underworld's capital city.
Rias arrived with her peerage; all dressed in formal attire.
The hall was already packed with young devils from the major families:
- The Sitri delegation, led by Sona
- The Bael representatives
- The Astaroth heirs
- The Glasya-Labolas family
- And dozens of others
At the center of the room, standing on a raised platform, was Lucien Gremory.
But where Caelan was cold and detached, Lucien radiated confidence and warmth.
He was dressed in formal Gremory crimson and black, his Power of Destruction crackling faintly around his hands.
"Welcome, everyone!" Lucien's voice carried across the hall. "Thank you for attending the Young Devils Gathering. We have much to discuss."
He gestured to a large screen behind him, which displayed a map of the three realms.
"As you all know, the Khaos Brigade attacked the Peace Conference two weeks ago. This was not a random act of terrorism. It was a coordinated assault designed to destabilize the newly formed alliance between the Three Factions."
Murmurs rippled through the crowd.
"The leaders of the Khaos Brigade include Rizevim Livan Lucifer—the original Lucifer's son—and various remnants of the Old Satan Faction. They are dangerous, organized, and well-funded."
More murmurs.
"However," Lucien continued, "they made a critical mistake. By attacking the Peace Conference, they united the Three Factions against them. Devils, Angels, and Fallen Angels are now actively cooperating to hunt down and eliminate Khaos Brigade cells."
He pulled up intelligence reports.
"Here's what we know so far—"
And he began a detailed breakdown of Khaos Brigade activities, known members, suspected hideouts, and strategic weaknesses.
Rias listened carefully, impressed despite herself.
Lucien has always been brilliant at politics and strategy. He's grown even stronger since I last saw him.
"—and finally," Lucien concluded, "we need to coordinate our efforts. Each of your families controls different territories. Different resources. If we share intelligence and work together, we can dismantle the Khaos Brigade before they launch another attack."
Applause echoed through the hall.
"Now," Lucien said, "I'd like to open the floor to discussion. If anyone has intelligence to share or concerns to raise, please speak up."
Sona stood. "The Sitri family has identified three potential Khaos Brigade safehouses in the human world. We're coordinating with local exorcists to investigate."
"Excellent. Thank you, Sona."
Sairaorg Bael stood next. "The Bael family is increasing security around our territory borders. We've also allocated funds to hire mercenaries for additional protection."
"Good thinking."
The discussion continued for over an hour, with various families sharing information and coordinating strategies.
And through it all, Issei couldn't help but notice one thing.
"Buchou," he whispered to Rias. "Lucien-sama is really good at this."
"He always has been," Rias replied quietly. "He's been groomed for leadership since birth. Politics, strategy, combat—he excels at all of it."
"He's like the opposite of Caelan-sensei."
"Not opposite. Complementary." Rias smiled sadly. "Lucien is the public face. The leader. The golden child. Caelan is the shadow. The strategist. The forgotten genius. They balance each other. Or they would, if they actually worked together."
"That's... sad."
"Very sad."
Part VIII:
Just as the gathering was winding down, the main doors burst open.
Everyone turned.
A figure walked in, flanked by a massive white wolf.
Caelan Lucifuge.
Dressed in formal Lucifuge silver and white, his expression cold and unreadable.
The hall went silent.
Lucien, standing on the platform, froze.
For a long moment, the twin brothers stared at each other.
Then Caelan spoke. "I received a formal invitation. As the head of House Lucifuge, I decided to attend."
"Caelan." Lucien's voice was carefully neutral. "I'm... glad you came."
"Don't be. I'm not here for you." Caelan walked past him toward an empty seat in the back. "I'm here because the Khaos Brigade is a threat to my territory. I want intelligence on their movements."
"Of course. I'll provide you with all the reports—"
"Just send them to my estate. I'll review them on my own time." Caelan sat down, Hoarfrost settling beside him. "Continue your meeting. I'm listening."
Lucien looked like he wanted to say something else.
But he didn't.
He just nodded. "Right. Well. As I was saying—"
The meeting resumed, but the atmosphere had changed.
Everyone was acutely aware of the Ice King sitting in the back, silently observing.
Judging.
Calculating.
After the meeting ended, several young devils approached Caelan, trying to introduce themselves or network.
He ignored all of them.
Except one.
Sona Sitri walked up to him, adjusted her glasses, and said simply, "Lord Lucifuge. I'd like to discuss trade agreements between the Sitri and Lucifuge territories. Are you available for a private meeting tomorrow?"
Caelan looked at her.
Then nodded. "Fine. My estate. Ten in the morning. Don't be late."
"I'm never late."
"We'll see."
Sona walked away, satisfied.
Leaving Rias staring in shock.
"Did Sona just successfully schedule a meeting with Caelan?"
"She did," Akeno confirmed.
"How?!"
"She didn't make it personal. She made it business." Koneko shrugged. "Smart."
Meanwhile, across the room, Lucien was watching his twin brother with a complicated expression.
He came. He actually came.
That's... progress.
Isn't it?
Venelana appeared beside her grandson. "Don't push him, Lucien."
"I wasn't planning to, GrandMother."
"Good. Because if you do, he'll leave and never come back." Venelana's expression was sad. "We've already lost twenty-three years. Let's not lose any more."
"I know."
They watched as Caelan stood, preparing to leave.
And then, at the last moment, Caelan glanced back.
His eyes met Lucien's.
For one brief second, something flickered in his expression.
Not warmth.
Not forgiveness.
But... acknowledgment.
I see you. I know you exist. That's all you get.
Then he turned and walked out, Hoarfrost at his side.
Leaving behind a room full of devils processing what they'd just witnessed.
The Ice King had attended a family gathering.
Hell had officially frozen over.
Part IX:
That night, back at the Gremory estate, Rias found her mother sitting in the garden, staring at the crimson sky.
"Mother?"
"Oh, Rias. Couldn't sleep?"
"No. Too much on my mind." Rias sat beside her. "Can I ask you something?"
"Of course, dear."
"What was Caelan like? When he was younger?"
Venelana was quiet for a long moment.
"He was... quiet. Thoughtful. Always watching, always analyzing." She smiled sadly. "Even as a child, he was brilliant. But we didn't see it. We only saw that he was weaker than Lucien. That he couldn't match his brother's power. And so, we... ignored him."
"That must have hurt him."
"It did. More than we realized." Venelana wiped away tears. "By the time we understood what we'd done, it was too late. He'd already closed himself off. Built walls we couldn't break through."
"Do you think he'll ever forgive you?"
"I don't know. Part of me hopes so. Part of me doesn't think I deserve it." Venelana looked at Rias. "But I'm grateful he's in your life. That he's helping you. Even if he won't help us."
"He's a good person," Rias said softly. "Underneath all the ice and anger. He's genuinely good."
"I know. That's what makes it hurt so much. We had a good son, and we threw him away because he wasn't what we expected."
They sat in silence for a while, watching the stars.
"Mother?"
"Yes?"
"I'm going to keep trying. To include him. To show him he has family who cares."
"Even if he pushes you away?"
"Especially then." Rias smiled. "Because someone has to."
Venelana hugged her daughter. "Thank you, Rias."
"You're welcome, Mother."
Part X:
A week later, the Gremory peerage returned to Kuoh Academy.
Summer vacation was over.
School was back in session.
And waiting for them in the Occult Research Club was a notice.
"What's this?" Rias picked up the paper.
Akeno read over her shoulder. "It's from the Student Council. Sona wants to schedule a joint training exercise."
"For what?"
"Doesn't say. Just says 'prepare for unexpected complications.'"
"That's ominous," Issei muttered.
"Agreed," Kiba said.
Xenovia frowned. "Do you think it's another Khaos Brigade attack?"
"Possibly. Or—" Rias paused as her phone buzzed.
A text from Sona: We have a problem. Norse mythology is involved. Meet me ASAP.
Rias's eyes widened. "Oh no."
"What?" Asia asked nervously.
"Norse mythology. That means—"
The door burst open.
Azazel strode in, looking unusually serious. "Kids. We need to talk. There's been a development."
"What kind of development?" Rias asked.
"The kind involving Loki. The Norse God of Mischief. He's planning something big. And it involves your territory."
Everyone exchanged worried glances.
"Here we go again," Issei sighed.
"Yep." Azazel grinned despite the serious situation. "Welcome back to school, kids. Hope you enjoyed your vacation. Because things are about to get very, very complicated."