The ocean is magical. No matter what occurs, it's all fleeting—— Only its waves and bubbles are allowed to be eternal, swallowing everything into loneliness.

The mysterious submarine that suddenly appeared is now quietly floating above the sea.

Only the cries of the pitiful 「Leviathan」 could be heard under the blue sky.

 Are you alright, Bianka-sama? O-Of course I am. I can handle getting wet from head to toe, this is nothing. ——Ah, thanks for the towel. What is this! T-This... What is it? Do you know something, old man? ...No, not a clue. I've never seen anything like this in my entire life. A ship made entirely of metal... tore apart the 「Leviathan」's belly as if it was made of paper. And it can even dive under the sea—— ——Are all ships from 400 years in the future this amazing? ..... Don't be so surprised by something of this level, old man. I'll have you know—— Our transport ship 「Hestia」 is 10.000 times stronger than that submarine! ...Not that we can bring any battleship to this world. Don't fret, old man! No matter who they are we'll do something about it! (Huh? The energy of the Holy Relic... hasn't recovered even a single bit?) Look! Someone is coming out of the submarine! ...They are raising a flag? T-That is—— ...A pirate flag? Four boats left the submarine. Three of them surrounded the 「Leviathan」 and began to tear it apart； The remaining boat headed to the small reed boat carrying three people. Bianka felt like her opponent this time weren't 「normal」 pirates. Because—— ——The boy that seemed to be the leader was panicking to be point it's impossible to believe he could be a pirate. H-Hello. ...Hello. U-Umm... I'm sorry... ...What? W-We... Seem to have killed your prey so... ...I'm very sorry. ..... So you came all the way here to apologize, captain? Ah—— I'm not the captain. ..... I-I should let Lalla-neesan explain it. Sigh... ...You're really hopeless when it comes to these things. Everyone, we're sailors from the amphibious ship 「Caledonia」. I'm Lalla, the boatswain. This is Jimmy, our engineer—— As you can see, we're pirates. We apologize for stealing your prey, but we'll be keeping it. As an apology—— Our captain wants to invite you all aboard the 「Caledonia」... ...Interested? …… Dim incandescent bulbs, fading paint, rusty nuts and aged but well maintained power cables. For Bianka Ataegina and Rita Rossweisse the 「Caledonia」 was a giant time capsule—— ——As if they had stepped into a novel by Jules Verne. Late 19th and early 20th century designs... ...Where did this 「amphibious ship」 come from? Err... are you asking me? Who else? Your engineer doesn't seem to be able to hold a conversation, there is no use in asking him. Hehe... Jimmy loves to talk—— But he's not confident enough around you yet. Right? Y-Yeah... I-I think so. ...So, where did this submarine come from? Going by your clothes you don't look like you're from the 20th century to me. Yes, we actually aren't. But don't be in such a rush—— From now on the captain will answer all your question—— I can't go stealing the spotlight from her. ... Come, the captain is waiting for you at the bridge. 20th century... or perhaps 21st—— Welcome aboard the 「Caledonia」! Captain 「Barbarossa」 welcomes you on behalf of the entire crew! Hm. You speak and act like an actor despite being a pirate. I sincerely thank you for praising the 「King's Men」. ...? ...By 「King's Men」 you mean Shakespeare's? The one and only. And playing the role of the pirate captain 「Barbarossa」 is—— ——「William Shakespeare」 herself. ...!? Well, if you don't like 「Barbarossa」 I can also act as 「Captain Nemo」. Though I don't know him very well. I just happened to find by chance the ship he abandoned. You made it yours? Exactly. On a peaceful morning, I was doing my vocal workout while facing the sea—— When suddenly, a loud sound was heard and a steel monster came out of a maelstrom—— There was no one in it and its logbook was incomplete. ...If you ask me, 「Captain Nemo」 and his 「Nautilus」 make for such a strange story. ...Is this supposed to be a joke? A joke? You could call it that. A joke from the play known as 「fate」. But I must admit—— Overthrowing order, changing fate, rebelling against the heavens—— It's all truly overflowing with fun. ...Is this a world without order? Oh my, does our nameless little 「knight」 care about order? Right. We should start by introducing ourselves properly. ...What? (How did we go from that talk to introducing ourselves?) I am Marian William Shakespeare from 16th century England, and the captain of the 「Caledonia」. If you don't like 「Marian」, you can call me 「William」 or 「Shakespeare」, I don't mind. (The 16th century, so 1500...?) This is our boatswain, Lalla Sayyida al Hurra. She's from Morocco of the same era as me. And this is James "Jimmy" Watt, an engineer from 18th century Scotland. The 「Caledonia」 got its name thanks to him——

Note：

喀里多尼亚（Caledonia）是古罗马时期的拉丁语地名，即今日的苏格兰地区。

 (...James Watt? The guy who made the first modern steam engine? But he looks younger that me...) ——「Nautilus」 wasn't a bad name, but the crew insisted on this new name to honor the Scottish boy for his excellent work on repairing the ship. Wasn't it you the one who wanted to change its name? And I didn't do anything impressive, I just followed the manual. ..... Ah, right. This is 「Iron Mask」. My chief officer and adjutant. ...A pleasure to meet you. She herself wishes for her identity to remain a secret, so please respect that and don't pry on her private matters. ...Isn't it a bit suspicious? Well, maybe that's how it looks to an outsider, but to me she's the most trustworthy and reliable person on this ship. ..... Understood. I won't press the matter of 「Iron Mask」's identity any further—— ——You and your crew introduced yourselves, I suppose it's now our turn. I am Bianka Ataegina, and this is my adjutant Rita Rossweisse. We're Valkyries, who under the orders of Schicksal, came to explore this world. .....? .....? ..... ...「Schicksal」? 「Valkyrie」? What's that? ...Huh? Ahahahahaha! ...? It seems your words were true, my dear adjutant, or should I say “teacher”! Ahahahaha! ...Director, have some moderation. Hey! What is this red haired shorty saying!? How can you not know Schicksal? Oh my. Don't scold me, young lady. What I'm saying... is the truth. I've never met any 「Schicksal」 and there is no one who goes by that name here. ...What!? ——But I know a little about them thanks to what 「Iron Mask」 told me. There are many worlds out there who are unusually full of an energy called 「Honkai」—— Ah~ Is it some kind of magical world? Worlds affected by this so called 「Honkai」 are under the constant threat of monsters and calamities—— ——And the one who rose against it is an organization called 「Schicksal」. There is no one who hasn't heard of 「Schicksal」 in those worlds. To fight against the monsters, Schicksal selects women with potential and turns them into soldiers, who they call 「Valkyries」. Said 「Valkyries」 can resist the corruption caused by the 「Honkai」, and use its power to fight for humanity. ——Self-proclaimed 「Valkyries」, are those things really true in your world? ..... ..... You phrased it in a strange way, but... Yes... That's the truth. Then listen, you two—— The advice I'm about to give you will be useful to you in the future, so make sure to pay attention. ...「Advice」? Yes. A very simple advice but of the upmost importance. Listen—— If you plan to survive in this world, make sure to not waste your ammunition. ..... I don't mean you won't be able to refill your energy anymore, but rather the recovery process will be 100 times slower than what you're used to. Similar to how the 「Caledonia」 can only carry six torpedoes even after its renovation. ...Or perhaps did the training you've undergone since a young age made it so you can't do anything without 「Honkai」? I'd appreciate if you didn't underestimate me! If you go that far... would you like to spar with me? I promise I won't use Honkai energy! Hahahaha! What will you do? Show off your melee fighting skills? I got an idea. Chief officer, do you feel like being this young lady's opponent? ...No thanks. Are you hated by your crew? ——But if the captain were to pay me for it... I will. Huh. Were you a money loving mercenary all along? Ahahahaha! Very well, I won't be able to call myself a good captain if I don't pay my troupe's salary! ..... ..... In that case, I have one request. ? If Shakespeare-san is sending her adjutant to fight—— ——Then I will be her opponent in behalf of Bianka-sama. Does that sound good to you? Hahaha! Interesting! ...Then, let's do the following. Bianka and me, Rita and 「Iron Mask」—— ——Each one will fight its respective opponent. Any objections? Haa...Haa...! So strong... That was an excellent fight. Lasting that long despite fighting using weapons and techniques you're not familiar with is worthy of respect. ...If you keep up your training, I'm sure your martial arts skills will surpass ours. Now that we released stress by exercising—— ——The real information exchange can start. ...? "What's the goal of your exploration?" In exchange, I will tell you the reason why the 「Caledonia」 sailed. ..... "No comment"? Say nothing and you will lose the opportunity to become a passenger on the 「Caledonia」. ..... Ugh... If there is something you don't want me to know—— Wait, old man! ...! You can stay. To us you're our comrade... so please don't think of yourself as an outsider. Let's get back on topic—— Rita, explain it to them. Tell them why we've come here. ...Understood, Bianka-sama. First—— Do you know what the 「Sea of Quanta」 is? In simpler terms, your mission is to enter a different dimension called the 「Sea of Quanta」 and explore a special structure known as the 「Ether Anchor Point」. Mathematically speaking, the 「Sea of Quanta」 doesn't belong to the known four dimensional space, instead our “here” is a 「Parallel World」 that exists in parallel to it. The 「Ether Anchor Point」 is a topological formation that exists between the 「dimensional manifolds」, and whether its origin is natural or man-made has yet to be discovered.

Note：

流形（Manifolds）是局部具有欧几里得性质的空间，是欧几里得空间中的曲线、曲面等概念的推广。一般的流形可以通过把许多平直的“片”“折弯”并“粘连”而成。

黎曼（Bernhard Riemann）是第一个广泛地展开“真正需要把流形推广到高维的工作”的数学家。事实上，"Manifolds"这个名词就来自于黎曼的德文术语"Mannigfaltigkeit"（中文里“流形”的称谓，则来自江泽涵先生的创意）。

 Unlike the 「classic dimension」 we live in, the 「Sea of Quanta」 is 「fragmented」 on a large scale—— Basic physical laws change continuously as the coordinates shift, resulting in the worlds being unstable like soap bubbles—— ——However, in the gap between said fragmented worlds, there are countless 「stable zones」 fixated by the 「Ether Anchor Point」. Those worlds, like ours, follow a fixed set of laws. This is my conclusion. Listen well, this is very important. The 「projection」 of the Solar System in the 「Sea of Quanta」 is very close to the 「coordinates」 of an 「Ether Anchor Point」. Which means, if someone were to get inside that 「projection」 in the 「Sea of Quanta」... ...One could possibly observe a 「clone of our Earth」. ——There is value in exploring something like that. Luckily for us, by using materials left by the previous civilization we were able to create several experimental devices which allow us to move back and forth between the 「Sea of Quanta」 and our world—— ——The name of that device is 「Genius」. In theory, by using the 「Genius」 a person is able to return from the 「projected worlds」 at any moment—— But if one were to start from this side, our 「reality」, it can only be used when an extremely rare 「space-time window」 appears due to technical difficulties. The next time the 「window」 will appear is on February 29th between 11:15 and 12:15, near the Fjord 1054 in the Northeast Greenland National Park. It will remain open for approximately 100 seconds. This event is rarer than the transit of Venus—— It could be centuries until the next 「windows」 appears. ——What do you think? Doesn't it make you excited? ...That's the simpler version of it. Our objective is to explore the 「Ether Anchor Point」—— Do any of you know anything about it? Not a clue... I didn't understand half the words you said, ahahaha. ...Doesn't sound much different from what you told me, Iron Mask. Multiverse or whatever. ...Perhaps. That 「Overseer」 knows his stuff. Then... I'll take over to explain the situation from inside the 「Sea of Quanta」.