A Few Days Later.
That morning, the sun shone gently above the horizon, bathing the ocean's surface in shimmering golden light. A soft breeze carried the familiar salty scent of the sea, and the cool afternoon air felt as if it wanted to soothe the wounds we'd endured through the past nights.
I stood at the edge of the deck, both hands resting on the ship's railing, which now showed its age—cracked, blackened, and roughened by relentless battles.
My gaze fell on our weary vessel. Her hull patched hastily, sails torn and hanging half-raised, and ropes dangling in disarray.
Every inch of wood that was scorched or scratched bore silent witness to those long, grueling nights of resistance.
The Sea Demons came relentlessly, attacking from the shadows. No time to rest. No time to breathe. Only the sound of splashing water, screams, and the roar of battle filling the night.
I took a deep breath.
"Still standing, huh…" I whispered quietly, as if speaking to the ship herself. "You're too stubborn, just like me."
Across the deck, I saw Atalanta standing still, arms crossed. Her eyes gazed sharply toward the horizon, but her expression hid something deeper—uncertainty, perhaps anxiety.
The wind blew through her long hair, making her look like a statue of a brooding huntress goddess.
Fujimaru and Mash were busy helping my little crew patch up the ship's damages.
Mash, full of spirit, lifted wooden boards and hammered nails, while Fujimaru smiled constantly, encouraging the tiny crew members who moved like hardworking ants—swift and tireless.
David crouched near a large hole on the deck, examining the cracked wood with a serious expression.
Paris lounged near the helm, swinging his legs over the railing in his usual relaxed style. On his head, Apollo perched in his small sheep form, eyes closed as if indifferent to the chaos around him.
I sighed and then sat down cross-legged, leaning against the railing.
My hand reached for the scroll tucked at my side, and the moment I touched it, it began to glow faintly with golden light.
Slowly, I unfurled it.
That golden light spread across the surface of the aged paper, and a single point began to appear on the northwest side of the map—pulsing softly, as if depicting an event in motion. A faint image of a pirate ship colliding with another vessel, but it was blurry.
"…A battle?" I muttered under my breath.
I didn't know who they were. But… somehow, my heart told me this wasn't an ordinary encounter. Something important was happening there.
Suddenly, a cheerful voice greeted me from the front.
"Heii, you look really serious. Don't tell me you found some treasure?"
I turned. Paris was now standing in front of me, having slipped down from the railing near the helm without me noticing. He wore a casual smile, one hand on his hip. Atop his head, Apollo—still in his fluffy sheep form—was gazing at the still-glowing map with wary eyes.
"You look very serious," Apollo said softly, his tone deep and calm. "Don't just stare at it. Tell us…"
I gave a slow nod and then moved my finger to the point where the two ships intersected.
There was no loud sound, only the faint brush of my finger against the map's surface, which continued to emit a soft, pulsing light from that location.
"I'm not entirely sure… but something's happening there," I said. "Something significant enough to be marked by this map… and vague enough to be hidden by the world."
I continued to gaze at the faint point on the map, its golden glow slowly dimming, as if whatever was happening there was being cloaked by a heavy fog. When I lifted my head, I saw Paris tilting his head curiously, while Apollo furrowed his tiny brows—yes, even a small sheep could look uneasy.
Footsteps began to approach. The sound of boots creaking on the wooden boards came from all directions. As I turned, the other members of the crew—Mash, Fujimaru, Atalanta, even David—began gathering around, drawn by the glowing map and the rare serious expression on my face.
Mash stood closest, leaning down to look at the map in my hand with worried eyes.
"Caster… what's going on?"
Fujimaru followed right behind her, sweat still trickling down his temple from helping patch the ship's hull.
"We saw the glow from afar. Is something happening?"
Atalanta approached with light but cautious steps, standing just behind the others, her eyes immediately locked onto the map.
David stared at me intently, then lowered his gaze to the map in silence. No words were needed. His eyes said enough—he too felt the bad omen in the air.
"A battle," I finally said. "Two ships, but no details. Only light and shadow. But enough to make this map react."
"In that case…" Paris slid a hand behind his head, his expression casual but with a faint edge of tension in his voice, "what are we gonna do, Caster?"
I looked at all of them—faces filled with hope, anxiety, and curiosity—with a serious expression.
In the brief silence that followed, I slowly closed the map.
The golden glow that had warmed us now faded away, leaving only tension and a looming sense of foreboding. I placed the scroll back at my side, but the weight it left on my chest remained.
I looked away, lowered my head slightly, and touched my chin in thought. My mind spun with conflicting possibilities.
'Should we really head to that point? But with the ship in this condition…'
My eyes glanced around. The hull still bore rough patches, the sails were torn in places, and the rigging hadn't been fully restored.
If we forced this ship into another battle—especially against a pirate vessel or some unknown entity—our chances of survival would be slim.
I took another deep breath, trying to still the storm inside my head. But then, like a spark in the darkness, a memory surfaced.
"Noble Phantasm…" I muttered. "I haven't used it since arriving in this singularity."
More precisely, Great Ram Nautilus. A Noble Phantasm that allows me to summon a replica of the legendary submarine owned by Captain Nemo—Nautilus. Not just a vessel, but a symbol of courage and the will to explore the unknown depths.
However…
"The problem is… I'm not sure how many people it can carry," I whispered to myself.
The submarine was sturdy and capable of infiltrating places no normal ship could reach. But it was just a replica—not the original Nautilus. It lacked full facilities and certainly couldn't accommodate our entire crew.
I looked again at the faces now waiting for my decision. Paris squinted curiously, Mash looked slightly uneasy, Fujimaru appeared ready to follow whatever plan I laid out, Atalanta stood calmly but with unblinking intensity, and David… as usual, he simply waited.
They trusted me. That's why I couldn't be reckless.
I drew in another breath, then lifted my head and faced them directly.
"There's something you all need to know," I said, my voice calm but loud enough for everyone to hear. "I have one Noble Phantasm I haven't used yet in this singularity."
They glanced at one another. Paris looked even more intrigued, and even Apollo, sitting atop his head, raised his little head.
"I can summon a submarine—Nautilus. A replica of Captain Nemo's vessel," I continued. "With it, we can approach that conflict point without being seen by enemies. But… there's one issue."
I paused for a moment, letting my words settle in.
"That submarine isn't large enough to carry all of us. Only a few can come. The rest will have to stay here… and continue repairs until I return."
Silence engulfed the deck.
The sea breeze, once comforting, now added a chill to the air. The faces in front of me had grown tense.
Yet none of them stepped back. Not a single trace of fear in their eyes. Even Mash and Fujimaru exchanged a glance and nodded quietly. Atalanta simply folded her arms, as if saying, "If this is your plan, then I'm in."
"Well then..." Paris raised a hand casually, his mischievous smile returning, "who's up for a dive into the heart of trouble?"
I gave a small nod, a faint smile escaping me despite the lingering pressure.
"In that case, let's decide who's coming on this mission," I said, my voice calm but clear. Each word seemed to echo in the sudden stillness of the deck.
Mash stepped forward first, her expression resolute. "If you'll allow it, Master and I will come with you."
Fujimaru nodded without hesitation, his eyes fixed on me. "We don't know what's waiting for us out there. But if it's dangerous, we have to go. If not, how can we call ourselves the Chaldea team?"
I looked at them for a few seconds, then nodded. Their courage was something I'd come to expect.
"What about the rest of you?" I asked, scanning the remaining crew.
"Then I'm coming too!" Paris chimed in, raising his hand. "A submarine, a stealth mission, a mysterious place—how can I not join?"
Apollo, perched atop his head, sighed quietly. "I have a bad feeling… but that's exactly why we can't sit this one out."
I looked at him. Paris's cheerful grin might have hidden sharp instincts. And with Apollo by his side, they'd make the perfect danger radar.
Then I turned to the small crew—the young girls who had become a part of this ship.
They were the ones who usually managed navigation, the engines, and communication. They looked at me with eager eyes.
"You girls… some of you were designed to operate the Nautilus, weren't you?" I asked.
Several of them nodded quickly. One of them—with a large blue ribbon in her hair—stepped forward. "That submarine can't be run solo, Captain. But leave the technical stuff to us."
"All right," I nodded. "Four of you will come with me. You know who's best suited."
I then turned to the two who hadn't spoken yet—Atalanta and David.
"I'll stay behind," Atalanta said without hesitation, arms crossed. "Someone has to guard this ship and protect the rest of the crew. If we're attacked, they won't last without a Servant."
David shrugged. "I'll stay too. Not because I'm scared or anything, but… if all the heavy hitters leave, what happens if the ones left get hit?"
"Fair point," I muttered. I could count on them to hold the ship.
"In that case," I said at last, "those going on this dive mission will be me, Paris and Apollo, Mash and Fujimaru, and four of the small crew. The rest—Atalanta, David, and the others—will stay with the ship, keep working on repairs, and stay alert."
A decision had been made. Beneath a sky slowly draped in wispy clouds, we split our strength—half to investigate, half to survive.
I stood up from where I'd been seated, rising in front of them.
"Get ready," I said. "Once everything is set… we'll summon the Nautilus."
And in an instant, the deck came alive. Some ran off to gather supplies, others hurried to tie ropes and adjust the sails. Among them, young faces glowed with resolve and excitement.
The sky might be darkening. But our spirit did not.
I turned back to stand by the ship's railing, the ocean wind now blowing stronger against my face, carrying the salt of the sea mixed with something else—tension, a premonition of battle.
The sea stretched out before me, vast and calm… too calm. And beneath that calm, I knew something was waiting.
I raised my right hand, slowly. My eyes fixed on the horizon.
This ship wouldn't be enough to carry us all. But the ship I was about to summon… was no ordinary vessel. It was the creation of one who dared explore the deepest seas. Who called the ocean his second home.
I aimed my hand toward the open sea, and began to recite the incantation I had prepared in my mind.
"In the silent ocean…
Where no light can reach…
Where the echo of truth sails far from the world…
Hear my call—and rise from the deepest depths of the abyss."
A magic circle began to form on the surface of the water, glowing a bluish-green as intricate lines spread like circuits. The wind started to twist unnaturally. The once-still sea began to ripple, as if it too heard the call.
I placed a hand over my chest, then thrust it toward the sea with a resounding voice.
"Set Sail—Great Ram Nautilus!"
In an instant, a whirlpool formed in the once-calm waters. From within that vortex, a light emerged… slowly taking shape. Iron. Machinery. A long, slender silhouette.
With a deep, resonating rumble—as if from the heart of the world—it surfaced.
Nautilus.
Its form was graceful yet sturdy, like a legendary ancient fish, with a body of bluish steel and copper ornaments lining its sides. The cockpit windows glowed softly, and a rotating starfish emblem spun slowly at its bow. The engines along its back pulsed faintly, beating like a heart newly awakened.
Gasps of awe rose from the crew.
"So smooth… like it had been waiting for us all this time," Mash whispered.
Paris gave a low whistle. "Cool! Seriously, this thing's got style."
Fujimaru stared at the Nautilus in amazement. "Is there anything you can't do, Caster?"
I let out a quiet chuckle at the question, but didn't comment.
Looking at all of them, I finally spoke.
"This is it. The ship that will take us toward that light… or perhaps, into the darkness that hides it."
And under a sky growing darker, with the ocean wind at our backs, we prepared to sail toward our next destiny.
.
.
.
Moments later, inside the Nautilus.
The soft light of the submarine's lamps pierced the dark ocean surrounding us. The low hum of the engines created a steady rhythm, soothing in its consistency. Beyond the thick glass windows, the underwater world stretched out—silent, still, but filled with a deep blue that swallowed everything.
Paris pressed his face up against the round window, his eyes sparkling.
"Woooow! This is amazing! The water's so clear even though it's dark—Apollo-sama, look! That's… that's a jellyfish, right?"
Apollo, perched calmly on Paris's head, replied softly,
"That's Deepstaria enigmatica. A rare jellyfish. It's usually only seen at extreme depths like this."
"Amazing! Apollo-sama knows everything!" Paris beamed.
Apollo chuckled quietly before responding to Paris's praise.
"Not really. My knowledge of the sea is limited. If you really want to learn about the ocean, you should ask Poseidon."
"Huh? Really?" Paris looked thoughtful for a moment, then suddenly turned toward me.
"Eh, eh, traveling under the sea isn't as scary as I thought… It feels more like a dream."
I only gave a small smile in Response, still keeping my hands on the controls, letting the Nautilus glide gently between coral formations and slow-moving currents.
In the distance, a school of silvery fish swam in formation, creating a pattern like a spinning star.
Mash, sitting beside Fujimaru, looked awestruck, her eyes fixed on the view outside.
"So silent and peaceful… it feels like we're exploring an entirely different world."
Fujimaru nodded, leaning back into his seat.
"Far from battle, far from conflict… it's as if time itself has stopped here."
I glanced upward—through the digital periscope, I could see the sunlight slowly fading as we moved deeper.
The layers of the ocean folded like mysterious curtains, unveiling a hidden beauty unseen by human eyes.
Some of the small crew members I brought along were sitting quietly in their seats, occasionally whispering to each other and giggling softly when they saw a sea turtle swimming slowly past the front of the ship.
Paris leaned forward again, pointing excitedly.
"Apollo-sama! That's a whale, right?! The really big one?!"
Apollo nodded calmly.
"Yes. Balaenoptera musculus. The blue whale. The largest creature in the ocean."
Paris gasped in amazement, watching the massive creature swim gracefully, its shadow drifting above the ship like a living warship.
"It swims like it's singing. Slow but… so beautiful."
And for a moment, none of us spoke. Only the sound of the ship's engine and the calming silence of the deep ocean filled the space.
.
.
.
After what felt like an eternity in the deep, a soft notification chime echoed through the control room.
"Approaching destination coordinates."
I turned toward the holographic map floating in front of me. I applied the glowing coordinate marker to the ship's system. The glowing point we had seen earlier was now just above our current position.
"…We're here," I murmured.
"Surfacing"
The Nautilus slowly began to ascend, leaving behind the still, dark ocean depths. Natural light began to filter through the ship's windows, signaling that the surface was drawing near. A faint vibration ran through the floor as the water pressure started to shift.
Paris leaned back into his seat, his hair a bit messy from the long journey. "Waaah… we finally made it, huh, Apollo-sama…"
Apollo, still perched on his head, replied quietly, "Don't let your guard down. I sense… something unusual above."
As the surface of the water broke beneath the ship's nose, the warm, blinding light of the setting sun greeted us. The sea appeared calm… for a few seconds.
"There…!" Mash stood up and pointed into the distance, eyes wide.
In the distance, two ships were speeding across the water. One—smaller, with tattered sails and a mast nearly broken—looked like a pirate ship. Its hull was scratched and scarred from battle, and a thin stream of black smoke trailed from its right side. The ship veered sharply, dodging shots from a much larger, more majestic vessel.
That chasing ship loomed like a floating fortress. Its hull was reinforced with layered steel, adorned with golden decorations and proud banners fluttering in the wind. From its tower, cannons were being readied—set to fire relentlessly.
"A battle?" Fujimaru murmured, then looked toward me. "That's not just any ship, is it?"
I squinted, trying to identify the silhouette of the larger ship. There was something about its design—an elegant yet haughty structure—that made me think… this wasn't man-made.
"No," I replied quietly. "It could be… a Servant's ship."
Paris had his face pressed to the window again, eyes wide and reflecting the dramatic scene outside.
"Apollo-sama… this looks kinda dangerous, huh?" he said, trying to smile despite the nervous tone in his voice.
Apollo stared intently at the grand ship, his voice low but clear.
"Yes. But this is a turning point. Either it's the truth we seek… or the beginning of destruction."
I nodded slowly, my mind racing. One ship was clearly trying to flee with everything it had left… while the other pursued like a predator long awaiting its prey.
The glowing point on the map—it wasn't a fixed location. It was the trail of an ongoing conflict, a battle still unresolved.
I took a deep breath and gave the command,
"Prepare yourselves. We're moving in… slowly."
***
Author note:
Damn these week really give me Hard Time, sorry for not updating for a while.
I just feel that Nautilus is hasn't make some debut so I make this chapter using Nautilus, y'know at first I just want to continue with only the pirate ship, but I just realized that because the restless attack from the sea demon at night make me thinking that the ship condition must so damaged. I thought it would give a slight realistic impression(even though I'm not sure if we're need that anyway)
Then I think about how can I continue? Should I just do it with the ship that damaged? But maybe I thinking one jump from Heracles is enough to make the ship sink so I better not continue using the ship.
Then I just realized that the mc has captain Nemo submarine (I nearly forgot about it, fortunately I re-read the fanfic so I was remember it again)
And so I think about make this chapter as Nautilus first debut!