The temporary Singularity had been dubbed "The Hot Spring of Eternal Spring" by the Chaldea staff, a bizarre distortion that manifested as an endless, sun-drenched resort town centered around a massive, intricately designed onsen. It was an assignment that felt more like a vacation—a necessary bit of downtime for the overworked Servants and Master Fujimaru Ritsuka. The anomaly was a gentle one, requiring more investigation and social maneuvering than outright combat, which suited Rider, Astolfo, perfectly.

He was practically vibrating with excitement, having been given free rein to explore by a Master who knew the futility of trying to contain the perpetually curious paladin. He’d spent his days sampling exotic fruit drinks, attempting to roller-skate on cobblestone streets, and generally being the life of every party.

It was in the secluded, traditional ryokan bathhouse that he found Saber, Artoria Pendragon.

Artoria, true to her nature, was taking a moment of solemn, quiet contemplation, enjoying the rarity of genuine peace away from the battlefield. She was still a king, even in a yukata, her posture regal despite the steam and the soft, borrowed cloth.

Astolfo, of course, broke the silence with the subtlety of a charging hippogriff.

"Saber-chan!" he chirped, gliding over with a skip, his pink braid bouncing. "Fancy seeing you here! This whole place is the best, right? The air smells like jasmine and... and maybe a little bit of those fried mochi things! You look super relaxed, though. Are you, like, finally taking a vacation from being so... serious?"

Artoria opened her green eyes, fixing him with a stare that held a practiced blend of patience and mild exasperation. She’d long ago accepted Astolfo as a whirlwind of chaotic good fortune, an entity she simply had to navigate rather than resist.

“Rider,” she acknowledged, her tone even. “It is a surprisingly pleasant Singularity. And no, I am merely resting. We are still on a mission.”

“Booooring!” Astolfo dramatically flopped down on the tiled bench near her. “Look, Master is fine, the anomaly is just excessive hot water, and we've already dealt with the one grumpy water sprite trying to hoard all the lemon shampoo. It's totally chill time!” He leaned in, his amethyst eyes sparkling with a familiar mischief. "Besides, I heard from one of the local spirits that the real fun here is in the private baths. The ones for... very close friends."

A faint, but distinct, blush rose on Artoria's cheeks. She knew that look. Astolfo’s relentless, honest flirtation was an ongoing phenomenon, one she found both utterly mortifying and—to her private, newly recognized feminine self—intensely thrilling. He treated her as a woman first and a king second, a reversal she was still adjusting to, but one that felt profoundly right.

She had spent a lifetime in denial, and now, away from the endless, bloody battlefields of her past, the freedom to explore this side of herself, with someone so genuinely affectionate and unburdened by expectations as Astolfo, was an unexpected gift from the Grail.

"Rider, your 'local spirits' likely misunderstood the term 'private,'" she said, attempting to maintain her composure, yet a small, involuntary smile betrayed her.

Astolfo simply grinned, reaching out to gently touch the smooth, toned skin of her shoulder. "Nah. I understood it perfectly. Come on, Saber-chan. Let me show you what a real vacation looks like."

The private bathing annex was a small, exquisitely maintained chamber, smelling of mineral-rich steam and cedarwood. The pool was large enough for two, but they hadn't even made it to the water. Instead, they had claimed the smooth, cool stone floor near the entrance, bathed in the soft glow filtering through the paper screens.

Artoria’s breath hitched, the sound muffled by the hot, damp air. She was braced against the smooth, tiled wall, her chest heaving, her eyes squeezed shut as a wave of sensation crashed over her. She felt the heavy, insistent pulse of Astolfo's hips against her backside, a rhythm that was fast and shallow now, driving her further into the exhilarating, chaotic spiral he always ignited in her. The force of it—that surprising, athletic strength hidden beneath his slender frame—made her knuckles white where her hands pushed against the wall for purchase.

PLAP PLAP SPLURT!

The sound was shockingly loud in the quiet chamber—the slick, fleshy impact and the wet expulsion of his seed against the sensitive skin of her buttocks and lower back. Astolfo let out a high, ragged groan of release, his arms bracing on either side of her, his taut muscles trembling as he collapsed forward, pressing his sweaty torso fully against her back.

“Ora ora, Saber-chan,” he panted, his voice thick with triumph and affection, his hot breath ghosting near her ear. “Giving up already?”

The question, of course, was purely rhetorical. Artoria's whole body was thrumming, her mind a dizzying mix of lingering shock and exquisite pleasure. Her head fell back slightly, her golden hair damp and stuck to her neck. She couldn’t form a coherent response, only a low, guttural noise of spent energy and lingering desire.

Astolfo didn't wait for an answer. He pulled back, his large, fully engorged cock slipping free with a wet, heavy sigh. He didn't move far, only just enough to turn Artoria's body so she faced him, her back now to the cool stone. He was beaming, the usual pink hearts bubbling around his image in her peripheral vision.

He reached for her, his grip firm on the outside of her thighs, spreading her knees wider as he knelt before her. The posture was a position of both worship and demand, one she had come to learn was his favorite.

"Nuh-uh. We are not finished, my King," he corrected, his purple eyes locked on hers, not with lechery, but with a vibrant, playful intensity that always melted her resolve.

Artoria could only look down, a helpless, breathless expression on her face as he positioned himself. His hard, thick length was inches from her lips, dripping with the mix of his own seed and the slick moisture they'd created.

"Hee hee, just try not to choke on my 'Saber'," he whispered, a smirk playing on his lips, referencing the sheer difficulty of taking all of him at once.

With a final, desperate sigh that was half surrender and half battle cry, Artoria leaned forward, her pride as a knight and her burgeoning desire as a woman coalescing into a single, determined action. Her hands found the slick, sweaty base of him, guiding the enormous head past her lips. The instant the velvety tip pressed against her throat, her eyes flew open, a primal, fierce determination burning in the emerald depths.

Throb. Throb. Throb.

The sensation was overwhelming: the warm, pulsing length stretching her beyond her limits, the heavy press of his testicles against her chin. It was a profound, complete possession that went beyond the physical, a feeling of being wholly taken that she had never allowed herself to experience before this beautiful, chaotic boy came into her life. Her world narrowed to the feel of him in her mouth, the scent of their mingled arousal, and the intense, dizzying heat of the singularity's air, making the already impossible act feel like a fever dream of pure sensation.