"Ahaha! A hail of cannon fire may not faze you, Comrade, but seeing this really caught you off guard, huh?" Belorussiya ughed, gncing at him. "Just look at it! Its massive size is big enough to accommodate some heavy vehicles!"

  Indeed, it would have been a lie to say he wasn't surprised by its sheer size and magnitude. The submarine alone could easily rival a two-story house, stretching as long as an average backyard pool. It roared with a deafening mechanical sound as half of its massive body rose from the icy depths. Then, with a heavy creak, the door to the interior slowly swung open, inviting them inside.

  "This is the ship we will take?" He asked, turning to the blue-haired woman beside him. "This is seriously something else..."

  Belorussiya urged him forward, and before he could hesitate, Volga offered her assistance with a smile, she summoned her rigging on the water as the twin-silver dragon heads greeted him. They gracefully lifted him, guiding him aboard the colossal submarine. The heads moved with surprising gentleness as they escorted him inside, their gleaming blue eyes seeming to watch over him protectively just like herself.

  As he got inside, Belorussiya guided him around while the other girls went their separate ways inside the Icebreaker Submarine to check the systems. Belorussiya shared some extensive history regarding the Icebreaker Submarine, expining that it was their test multifunctional tactical submarine, developed independently by the Northern Parliament.

  She said the submarine was created through the fruitful research of the Wisdom Cube power supply and was capable of fighting for itself. When submerged underwater, it could engage enemies in battle and had recently been utilized in the battles of Winter's Crown and Siren's Stronghold. This capability was a significant factor in the decreasing presence of Siren submarines during their missions.

  The Icebreaker Submarine boasts a massive arsenal, providing excellent firepower coverage for its operations. Its design allows for seamless navigation through the Arctic region, including areas covered in ice, making it a formidable presence in hostile waters. With the capability to remain submerged for extended periods, this new css of ship sets high expectations for performance in future conflicts, enhancing the Northern Parliament's strategic advantages in naval warfare. Belorussiya was proud of it, and definitely has a high expectation for its performance in the upcoming future battle.

  “No major faction knows this submarine even exists…” he murmured.

  “Correct! We’ve kept it a secret for a long time. You’re the first person to see it in person—and you might very well be the st,” she mused with a sly grin.

  "So, based on what I've seen so far, Arcana Sanctum is located deep underwater, right?" he asked Belorussiya as she opened the door to the command room.

  She paused and gnced back at him. "In a sense, yes. We're about to embark on quite the underwater journey."

  Greynar nervously chuckles. "I hope we don't stumble into any Siren ships,"

  As they settled into the room, the submarine began its descent. Once the submersible was fully submerged, the dim lighting brightened, illuminating the sleek, futuristic technology within. Panels, radars, and the command table glowed with a soft light, showcasing the advanced systems designed for their mission. The tech was truly advanced to the point it can't be compared to Eagle Union as far as he knows.

  The submersible descended slowly into the icy depths, gliding beneath an enormous iceberg. As they navigated around its frozen mass, a rge structural building emerged from the shadowy depths, gradually revealing itself beneath the water’s surface. The icy waters swirled around them as the submarine carefully approached the hidden structure.

  The Commander moved closer to the window, his eyes widening as he gazed at the structure. A road seemed to be carved down the middle, and coupled with the rge number of neatly cut icebergs floating quietly on the sea, the scene was enchanting. Two massive strips rose upward from the water's surface, creating an otherworldly atmosphere. The entire space was imbued with an unreal sense of fantasy.

  As the submarine came to a stop, Belorussiya instructed him to wait patiently while they checked the surrounding area first. Left alone with Volga, who remained silent, he turned to her and asked, "Sorry for the interruption, Volga, but what were you saying back there on the surface?"

  The carrier, who was gazing out the window, gnced at him and sighed wearily, as if she had witnessed something exhausting. "Commander, if... I know what happens in the future, would you believe me?"

  "Huh..." He tilted his head in confusion. "That came out of nowhere..."

  "Sorry, never mind that question." She silently gazed back out the window, her eyes appearing less vibrant than they had just this morning.

  'Something is strange with her. Is this what the Observer meant?' he mused silently, turning his attention back to the stunning scenery just as Belorussiya approached to inform him that he could go outside.

  As they stepped outside, the Commander tapped his feet against the ground, finding it surprisingly solid. The scenery around them was breathtaking, and something deep within him hinted that this was Observer's work.

  "This is still underwater, right?" he asked, gncing around at the sky above.

  "To be precise, this is a unique space beneath the water, somewhat like a mirror-like sea. It’s a bit complicated to expin, but that’s where we are, Comrade," Kirov replied.

  "It's been a while since I've touched this ground," Tallinn said, her eyes darting around the area. "Well, it's good to be back again."

  "I have a hunch that our second time here will bear fruit~" Murmansk mused happily. "I'm sure the Commander will unlock the mystery behind Arcana Sanctum."

  "You're joking, as if it were that simple," he replied, eyeing the heterochromatic girl with a raised brow. "And if it were true, I'd be suspicious as hell about it."

  The girl giggled softly. "Hehe~ I meant it as a supportive praise, Commander."

  "Yeah, yeah," he rolled his eyes. "Let’s get this over with then."

  "Commander, you can take the submarine as your command ship. We'll form a defensive formation around you," Belorussiya said, gesturing for him to head back inside.

  He nodded and stepped back inside the submarine. The engines hummed to life, and slowly, they began to move, gliding around the area with caution. Following the track that led to the entrance of the Arcana Sanctum, the submarine pressed forward into the unknown depths.

  As they navigated the smooth path, Greynar's gaze wandered over the road and the surrounding icebergs. His mind started drifting toward the potential of recreating a simir technology in the future. The seamless design of the passage, the way the icebergs hovered quietly in the water, and the stability of the entire structure—it all made him wonder if something like this could be replicated one day. This was not just a stroll through an underwater marvel; it was a glimpse of what the future could hold.

  “These floating icebergs… they seem to be at least a hundred meters in size,” he remarked, peering out the submarine window in awe. The sheer magnitude of the ice formations was astonishing for him to ignore.

  “Well, to be precise, they range from about 50 to 200 meters,” Tallinn added. “For such rge portions of the icebergs to be exposed above the water, the submerged part should theoretically be even bigger. However, our scans show that these icebergs don’t have much structure below the surface. Instead of floating, it’s more like they’re anchored in pce, fixed to the water’s surface.”

  "Then these iceberg might be a part of the Mirror Sea?" He asked curiously.

  "Not only that!" Gromky chimed in. "The mirror sea here periodically spawns Siren defense modules. Although they’re outdated and not very powerful, we can't overlook them. Per our orders, we have to return here regurly to sweep out any enemies that appear, and sometimes these icebergs get split apart by stray fire..."

  "And when we come back ter, the icebergs just reform as if nothing ever happened," Belorussiya added.

  Hearing that, the Commander shuddered. Observer's technology was far more advanced than he had imagined. After all, she was the one who had created this Sanctum in the first pce, leading him right into its depths.

  "Ice capable of regrowing itself...?" He tilted his head, baffled by the idea. It was something completely out of the ordinary—ice that could regenerate on its own was unheard of.

  "That's right! It's amazing!" Murmansk excimed pyfully as she stabbed the ice beneath her, picking up a shard of it. "So we kept experimenting. If it's a normal break, the ice just re-condenses." She casually tossed the piece aside and continued, "But if it's blown to bits, the fragments sink into the water, and after some time, an identical iceberg floats back up!" To demonstrate, she fired her turret, bsting the ice shard into the air. Moments ter, the ice beneath her repaired itself, good as new.

  "The Siren Mirror Seas we've encountered so far can be roughly divided into two categories," Kirov began, her eyes scanning the area warily for any potential ambush. "One type serves as an arsenal for producing chess pieces and mass-produced units. The other is an experimental field filled with all sorts of exaggerated equipment." She paused, taking in the frozen surroundings. "But this one... the Mirror Sea discovered by the Northern Parliament—perhaps the first one ever found by humanity—it's different. We've conducted extensive long-term research here, gathered as much data as possible, and analyzed every sample we could get our hands on. Yet, we still don't know why this pce exists. It appears to be nothing more than a preserved ndscape, hidden beneath the water."

  "Then what's your theory?" he asked.

  Kirov hesitated for a moment before answering. "Our guess, Comrade Commander, is that the Mirror Sea may not have been designed as a weapon for attack, but rather as a tool for concealment and evasion."

  "Hmmm..." Greynar hummed, mulling over their conversation. "You're right. Based on our recent encounters with the Sirens, every Mirror Sea we've seen has been hidden from the outside. But once we entered, the entire field was visible to us, like a world within a world."

  Tallinn added, "As for all the attacks we've seen both from and inside the Mirror Seas, those might just be products of the equipment stored within. I worked with Iron Blood for a period of time in the past, and they have been conducting research reted to Mirror Seas for a long time."

  "The impression I got was that Iron Blood initially wanted to monopolize the fruits of their research on Siren technology and refused to join the other major powers in Azur Lane for that reason," Kirov said with a smile, shrugging. "It’s ironic that Iron Blood, which was never the Sirens' primary target, suffered considerable losses due to its active attacks on them."

  "Iron Blood has always maintained a high interest in Siren technology," Tallinn said. "Before I left, they had successfully disassembled the components of the Mirror Sea. Although I'm not sure if they're still conducting technical tests on Mirror Sea technology, I can assume they've made progress based on their recent movements."

  'Hmmm... Speaking of the Mirror Sea, the st thing I remember was the Siren's mainframe, which is the core of the Compiler's system. During the battle at Scapa Flow, her mainframe was hidden beneath the Mirror Sea, wasn't it? Also, the one from my dream after we got back from the Royal Navy. It eerily resembled a Siren's mainframe.' The Commander thought to himself.

  "...Oh, everyone be careful! I received readings from my pne that a Siren defense fleet has appeared, and they're all humanoids!" Volga announced, recalling her recon pne and preparing to unch her fighters.

  "Seriously? We cleaned this pce out not that long ago..." Murmansk groaned.

  "They're certainly old models," Greynar commented wryly.

  "The enemy models in the Arcana Sanctum have never been upgraded. They’re exactly as they were when this pce was discovered decades ago," Kirov said, squinting at the distant enemies. "Back then, the Sirens that wrought such destruction and suffering upon humanity looked just like this. But now, these foes are hardly worth our attention. Comrade, time is precious. Let’s end this quickly!"

  The girls raised their voices in unison as they aimed their rigging at the humanoid models in their path. Greynar joined in as his submarine unched a torpedo, even though there was no water present, it worked fine and exploded to the enemy. Belorussiya unleashed a barrage of high-explosive ammunition, raining down fire on their foes.

  The clueless humanoid Sirens, alerted by the explosions, quickly deployed a barrier to defend their fleet as the humanoid carrier unched its fighters. But the girls were ready. The cruisers swiftly prepared their anti-air turrets, while Volga provided support from the rear, intercepting any incoming threats and preventing damage to the submarine.

  "Gremyashchy, Gromky! Charge at the battleships! I'll cover you from behind!" Kirov commanded, her turrets locking onto the humanoid destroyers fnking them. "Uraa!!!"

  With a shout from Kirov, the two Northern destroyers dashed forward, using their speed to circle around the frontlines and head straight for the Siren battleships in the rear. Salvos rained down on the humanoid Sirens ahead, while Belorussiya's supporting barrage tore through their defenses, causing enough distraction for the destroyers to break through.

  With a bright, cheerful expression, Gromky raised her arm high, and a chain made of shimmering ice materialized from her rigging. Gripping it firmly, she swung the ice chain effortlessly towards a humanoid battleship, the impact sending a shockwave through its hull. Gremyashchy, not far behind, followed suit, swinging her massive fil with precision. It smashed into another battleship, the force causing the nearby carrier to shudder as it was caught in the colteral damage. The coordinated assault was swift and brutal, catching the Siren fleet off guard.

  Being a low-tiered and outdated Siren defense fleet, the humanoid models stood no chance against the Northern Parliament girls. Within moments, they were completely overwhelmed and thrashed by the coordinated attacks.

  After obliterating the enemies along the way, the fleet arrived at the foot of a colossal iceberg. Unlike the others, this particur iceberg was said to house an internal structure—a facility that stood apart from the rest. According to the information they'd gathered, this iceberg was also the location of the fabled "door" leading into the mysterious "Secret Room." Its towering presence loomed ominously before them, as if guarding the unknown secrets within.

  "We've arrived, Comrade Commander," Belorussiya said, stepping toward the gate-like entrance.

  "This facility is where we first recovered vital information. Spectacur, isn't it, Comrade Commander?" Kirov added with a proud smirk, her gaze fixed on the structure. "It wasn't as easy back then as it is now. When we first came here, we faced countless Siren fleets, and it was only after the struggle and sacrifice of many naval martyrs that we finally cleared them out, securing this pce."

  "The discovery of this pce was a true turning point in our fate," Belorussiya said, her hand brushing the cold surface of the entrance, a look of deep reminiscence crossing her face. "It was thanks to the intelligence we recovered here that the Northern Parliament, once on the verge of colpse, managed to maintain its fragile defense line and rise to power once more. And beyond that, we began to unravel the secrets of the Sirens."

  "Man... That was some time ago," Tallinn remarked with a low whistle as she took in the sight of the iceberg. "I wish I could’ve joined in with you, but back then I was still with Iron Blood."

  Belorussiya nodded thoughtfully. "This is one piece of information we’ve kept under wraps. After so many leaks, we lost trust in Command’s ability to keep secrets. But we believe you, Comrade Commander, deserve to know this."

  Greynar stepped outside to join them, inspecting the towering structure before him.

  “A secret of the Sirens? Don’t you mean something reted to their origin?” he asked.

  “Correct. I’m not asking you to hide the truth from Eagle Union Command. I just hope that after you hear it, you’ll consider which parts to share, when, and how,” Belorussiya replied with a smile. “All the information you learn in the Arcana Sanctum today should be treated with that in mind.”

  The Commander nodded, aware that their origin was tied to the cruel million years of experimentation for the Awakening of a KANSEN. "I will keep that in mind."

  “The mystery of the Sirens is profound. As you know, they behave like machine-like entities, yet we still don't understand the true objective of their nature,” Belorussiya began. “Commander, did you know that the separation of Iron Blood and the creation of the Crimson Axis were all reted to the Sirens?”

  “Yes, I know that.”

  “Right. We all think so, too, but it goes deeper than that. What purpose do the Sirens serve? All these incidents lead us to one conclusion: it’s all an orchestration pyed by the Sirens to toy with us,” she said, her eyes closed. “Their attacks on us can almost be likened to a child pying with a toy. As we dug deeper into Siren technology, we realized just how far behind ours is.”

  "They also spoke of this time or old era as if they had lived through it," Tallinn said. "I couldn't care less about what they said, but they certainly talked like some weird old folks."

  "Well, you're not wrong," Greynar gnced at the cruiser. "They might just be 95% from the future."

  "As for the origin and true purpose of the Sirens... unfortunately, we haven't grasped it yet. But we're certain that all the answers lie behind the gate in front of us." Belorussiya said, nodding toward the Commander.

  "So you're saying, the objective of bringing me here was... about this gate, right, Belorussiya?" he asked curiously, knocking on the solid, blocked entrance.

  "Mhm... Exactly. Now that we've arrived, we can finally dive deeper into the mysteries of the Sirens," she replied with a subtle nod, her eyes gleaming with anticipation.

  He pushed open the heavy concrete door, revealing a narrow hallway. The atmosphere was dim and cold, with only the faint hum of hidden machinery resonating through the space. At the far end, a control panel flickered with faint lights, hinting at its purpose.

  "Well... this is going to suck," he muttered, gncing around the stark, confined room with a sigh.