Disclaimer: I do not own Highschool DxD, Hades and 'High school dxd: The Son of Indra' by 'thunder_god18'. They belong to their respective owners.

Enjoy.

The obsidian gates of Tartarus shimmered, not with light, but with an inner darkness that pulsed like a heartbeat for beyond, the Gremory Family stood, a regal tableau amidst the eternally twilight realm.

Sirzechs Lucifer, his crimson hair a stark contrast to the somber landscape, stood at the forefront, his wife Grayfia Lucifuge, ever composed and elegant, flanking him.

Venelana Gremory, her red hair gleamed as she held a curious, yet respectful, gaze, while beside her, her husband, Lord Gremory, radiated quiet strength.

And of course, Rias Gremory, the Crimson-Haired Ruin Princess, stood slightly ahead of her parents, her vibrant aura a beacon of devilish majesty.

Before them, the air crackled with an ancient power that was both chilling and captivating as two figures emerged from the shadows, radiating an aura of authority that dwarfed even the most formidable devils.

Hades, God of the Underworld, Lord of the Dead, materialized first, his presence being a tangible weight as he stood taller than Sirzechs, with dark, piercing eyes that seemed to see into the very soul as it is his regal robes that were the colour of midnight, embroidered with silver threads that depicted scenes of the afterlife.

Beside him, Persephone, Queen of the Underworld, graced them with her presence as her beauty is ethereal, like a blooming flower in the darkest night, garbed in flowing robes of deep green and gold, she exuded a gentle warmth that softened the austere presence of her husband.

"Welcome, House Gremory," Hades' voice resonated, deep and sonorous, echoing off the unseen walls of his domain. "You may already known me as Hades, God of the Underworld and of course, and this is my Queen, Persephone."

Sirzechs bowed deeply, followed by his family. "Lord Hades, Queen Persephone, it is an honor. I am Sirzechs Lucifer, also known as Satan Lucifer, and these are my family, Lord and Lady Gremory, my wife Grayfia, and my sister, Rias Gremory."

Persephone offered a gracious smile. "The honor is ours, Lucifer. We have long anticipated this meeting. Come, let us speak within our Palace. The chill of Tartarus is not conducive to pleasantries."

They followed the divine couple through the gates, the ominous landscape dissolving into a surprisingly grand, albeit darkly opulent, palace as black marble pillars reached towards a shadowy ceiling, flickering braziers casting eerie light upon tapestries depicting scenes of both beauty and terror.

They were led to a spacious chamber, large enough to accommodate both families comfortably as servants of sorts, beings wreathed in shadows and whispers, offered refreshments – nectar and ambrosia for the Gods, and fine wine for the devils, anticipating their customs.

Once seated, the air became thick with the weight of diplomacy as Sirzechs began. "Lord Hades, Queen Persephone, as you know, the Underworld is a realm of significant, shall we say,…activity. The Fallen Angels, stray devils… they often find themselves drawn to your domain. An alliance, a mutual understanding between our families, could greatly benefit us both in maintaining order, and… perhaps even forging a stronger future."

Hades steepled his fingers, his gaze penetrating. "Indeed, your observations are astute, Lucifer. The chaos of the human realm and the celestial realms often bleeds into my domain. An alliance with a powerful devil family, one known for its…resolve, is not unwelcome."

Persephone added, her voice softer but equally firm, "We have watched your House Gremory, Lucifer. Your principles, your strength, and your… compassion. They align with certain values we hold dear. Furthermore," She glanced at Rias, a knowing smile gracing her lips, "A union between our houses would solidify such an alliance in a way mere words cannot."

Rias blinked, her mind catching up. A union? Her eyes widened slightly as she glanced at her brother, who offered a subtle nod. This was more than just political maneuvering; this was about cementing a bond through marriage.

Just then, another figure entered the chamber, his presence less imposing than Hades, but radiating a youthful energy that was almost… electric. He had dark, unruly hair like his father, but his eyes were a vibrant green, full of restless curiosity. He wore simple, dark clothes, more practical than regal.

"My apologies for the delay," He said, bowing slightly to his parents before turning to the Gremory family. "I am Zagreus, Prince of the Underworld, son of Hades and Persephone."

Rias' breath hitched slightly.Thiswas the union? This washim? Zagreus turned his attention to her, his green eyes meeting her crimson ones, a flicker of surprise crossed his face, quickly replaced by polite curiosity.

"Rias Gremory, I presume?" He asked, his voice surprisingly gentle, devoid of the booming resonance of his father.

"Yes," Rias replied, regaining her composure. "It's… a pleasure to meet you, Prince Zagreus."

"The pleasure is all mine, Princess Rias," he said, a faint smile playing on his lips. "Though, forgive my bluntness, this… arrangement… it is rather… unusual, isn't it? Gods and Devils? It's not exactly a common pairing."

Rias raised an eyebrow, appreciating his honesty. "Unusual, perhaps. But considering the circumstances and the potential benefits for both our families, it's… logical, in a way. Though, I admit," she added, a touch of her usual teasing spirit returning, "I was rather expecting a fearsome, brooding Prince who ruled the Underworld, not… well, you."

Zagreus chuckled, a genuine, unguarded sound that surprised even himself. "And I expect a terrifying Devil Princess that has the intention on world domination. Perhaps we both had the wrong expectations."

The tension in the room eased perceptibly as their children's conversation began to flow. Sirzechs and Hades continued their more formal discussion about alliances, territory, and shared threats, but their glances often drifted towards Rias and Zagreus, who were now in a more animated discussion.

"Come," Zagreus suddenly said, gesturing towards a doorway leading out of the chamber. "There's someone I think you should meet. He's… a little rough around the edges, but he's got a good heart."

Rias, intrigued, followed him as they stepped into a vast courtyard, paved with dark stone and lit by strange, glowing flora and in the center of the courtyard is a truly enormous kennel, easily the size of a small house and from within came a low, rumbling growl.

Zagreus approached the kennel, whistling softly as the growling intensified, then suddenly shifted into excited barks as from out of the kennel sprang a creature that defied description.

It is a hound, undeniably, but a hound of nightmare and legend as it's three massive heads, each with rows of razor-sharp teeth and eyes that burned like embers, emerged, followed by a colossal, muscular body covered in dark fur.

This is Cerberus, the Hound of Hades, Guardian of the Gates of the Underworld.

Rias instinctively tensed, her devil power flaring slightly as the creature radiated pure, untamed power. She had once encountered great power like no other but these, this is incomprehensible to her.

That and she doesn't know how to exactly fight in battle.

But then, something utterly unexpected happened as Cerberus, upon seeing Zagreus, transformed as it's three heads began vying for attention, whimpering and whining like oversized puppies as it's massive body wiggled with delighted excitement.

Cerberus is… happy to see Zagreus as he licked Zagreus' face with tongues the size of blankets, knocking the Prince slightly off balance with his affection.

Rias stared, utterly dumbfounded as the terrifying beast she is seeing… is now acting like a playful golden retriever.

Zagreus, laughing, scratched Cerberus behind one of his ears. "Easy, boy, easy. Down now." Cerberus, surprisingly obedient, lowered himself to the ground, still panting happily and wagging his three tails with enough force to stir up a minor dust storm.

"Rias," Zagreus said, turning to her with a grin, "This is Cerberus. Cerberus, this is Rias."

Rias cautiously approached, still wary. Cerberus, however, upon seeing her, stopped wagging and stiffened as all three heads turned towards her, and a low growl rumbled from deep within his chest, a growl that is distinctly not playful with his fiery eyes narrowed, assessing her, judging her.

Rias felt a prickle of disappointment.

Of course, this magnificent creature, so affectionate with Zagreus, saw her as an outsider, a threat.

But she stood her ground, meeting Cerberus' gaze directly, but the growl didn't lessen.

In fact, it seemed to intensify.

"He's… not exactly taking a liking to me, is he?" Rias said, a hint of amusement in her voice despite her slight irritation.

Zagreus sighed. "No, not yet. Cerberus is… protective. Especially of me and my family. Devils aren't exactly his favorite beings. It'll take time for him to trust you." He reached out and stroked Cerberus' massive head reassuringly. "He'll come around. He just needs to get to know you."

Rias watched this exchange, a small smile forming on her lips.

Zagreus, despite being a Prince of the Underworld, possessed a gentle kindness, a genuine warmth that radiated outwards.

He was nothing like Riser Phenex, her former fiancé, who had been arrogant, possessive, and cruel.

Riser had seen her as a prize, a trophy. Zagreus… Zagreus saw her as an individual, someone to be introduced to his… giant, three-headed puppy.

Back in the palace chamber, the families were finalizing their agreements as Sirzech and Hades shook hands, a pact sealed not just in words, but in the potential union of their children.

Venelana and Persephone discussed gardens and nectar recipes with surprising enthusiasm, while Lord Gremory and Grayfia observed everything with their usual air of competence.

As Rias and Zagreus returned to the chamber, the atmosphere has become lighter and more relaxed as Rias caught her mother's eye with Venelana gave her a knowing, encouraging smile as Rias returned it, a newfound determination sparking within her.

Later, as the Gremory family prepared to depart, Rias approached Zagreus. "Thank you," she said softly. "For… showing me Cerberus. And… for being honest."

Zagreus smiled, a genuine, warm smile that lit up his features. "Thank you for not running screaming when you saw him. And for… being open to this whole… unusual arrangement."

He paused, then added, "Perhaps… perhaps we could… get to know each other better? Officially, I mean. For the sake of the alliance, of course." He blushed slightly, a charmingly awkward gesture.

Rias chuckled. "Officially, of course. It would be… beneficial for inter-pantheon relations."

As the Gremory family stepped back through the obsidian gates, leaving the Underworld behind, Rias looked back one last time.

She couldn't deny the strange fluttering in her chest as the Underworld, once a place of fear and shadows, now held a different kind of intrigue.

And perhaps, just perhaps, an arranged marriage to a Prince of the Underworld, who loved giant, three-headed puppies and possessed a surprisingly kind heart, wasn't such a terrible fate after all.

In fact, it might just be the beginning of something extraordinary, something that transcended duty and alliance, something that might even blossom into… something more.

The thought made Rias Gremory, the Devil Princess, smile for in the future, shrouded as it was in the mysteries of the Underworld, suddenly seemed a lot brighter.

Well, here it is...

All done...

As always...

Ciao...