Azur Lane Academy, January 2nd:

Prince of Wales: Have we made any progress in studying the Black Wisdom Cube?

Langley: I afraid not. With a lack of knowledge about Wisdom Cubes, we were unable to analyze it. 

Cleveland: The glow is getting stronger.

Prince of Wales: Knowing the Cube is related to the Sirens, we should assume it's something that bodes ill.

Akagi: Akagi is the worst! Why does she have to cause so much trouble for us?

?????: It's because of me.

A Sakuran kitsune with white fur entered the academy to everyone's confusion.

Prince of Wales: Who....is she?

Cleveland: I thought Kaga was the only large kitsune ship with white fur among Sakura Empire (large ship = any ship that is equal or bigger than a heavy cruiser)

Akashi: I know that face....How can she be here? Amagi, why are you here? I thought you're dead!

Hornet: Wait that's Amagi? Since when did she rise from her grave and dyed her fur white?

Amagi: How I come back to life is but a secondary matter in the present, it will be explained later. Matters regarding the Black Wisdom Cube is of the greatest urgency.

Akashi: Amagi, what does you mean "It because of........ My God, don't you tell me....Akagi created the Orochi to resurrect you?

Amagi: Precisely so, Akashi.

Akashi: Do you need someone to inform you about events after your death?

Arthur: It's not needed. I have done so already. 

Kure Naval Port, Sakura Empire:

Kaga: You want to seal away the Orochi?

Nagato: Temporarily. We just want to pause it. With Akagi gone, we can't push forward.

Kaga: Who made the decision? Without the Orochi, Sakura Empire will have no future.

Nagato: It was my decision. Akagi's disapperance is taking a toll on you, Have some rest.

Kaga: How dare you?

Nagato: As the replacement for Musashi-sama, I ordered you to comply. My decision is final. Dismissed.

Nighttime:

Ise: *drinking sake* Thing are starting to look grim. The Cube's falling into zur Lane's. hands, Shogun Musashi supposedly dead, and now Akagi missing in action...The future seems bleak for Sakura Empire.

Hyuuga: Not to mention the lack of response from the mass-produced ships.

Takao: I started to feel worry about Ayanami and Akashi...I hope they aren't abandoned & feeling lonely on their own.

Shoukaku: This whole plan was destined to fail from the start. We should not have trusted something we know nothing about?

Hiryu: We must not let Iron Blood know about our weakness. Crimson Axis isn't a monolithic alliance.

Hyuuga: And don't forget, the Sirens are still our real enemy.

Flashback to September 15th, 1959, in the cavern that would house Orochi:

Observer Alpha: *to Akagi & Kaga* At this rate, the Sakura Empire, no....the entire world will have no future. You will need power comparable to gods. This Black Wisdom Cube has the ability to collect all forms of data and evolves. For those like us, data is will, and will is power. That's why the ship born form the Black Wisdom Cube will have great power. Power to reshape the past and generate whatever future you desire.

Kaga: This is nonsense.

Observer Alpha: You can create anything. Even bring back the dead.

Akagi: Nonsense. Even if it has the same appearance and memories, it would still be a mere reflection.

Observer Alpha: You are wrong. If the shape and contents are the same, then it is real. But what is real, anyway? *teleports close to Amagi* The only that matters is Amagi will be back by your side.

Back to Pearl Harbor, while everyone was having a meeting about future plans, Halsey came to inform everyone of an approaching enemy fleet. 

Arthur: *via speaker* All hands on battlestations! An enemy fleet is approaching fast towards the base. I repeat, all hands on battlestations!

Within minutes, every gun is ready for action, preparing for the attack. A huge Siren fleet soon appeared on the horizon, leading the assault were an Elite Siren - Purifier. Normally, the appearance of an Elite Siren would require the efforts many shipgirls to strike them down due to their strength - enough to make even the most powerful shipgirls a run for their money. But today Purifier found her match. Together with the Sakurans, Halsey and Yamamto stopped her advance dead on its track, separating the Siren from her (supposed) goal - the Black Wisdom Cube. However, she was just a distraction.

In Arthur's office:

Viktoriya: The Black Wisdom Cube is ready to be moved to the underground vault, my master. We must go while everyone is keeping her at bay.

Before they can go, a portal suddenly opened in front of them, from it came a pale-skinned woman, who knocked Viktoriya aside and seize the cube. She was none other than Arbiter III: Empress.

Arthur: Well well well, what have we here?

Empress: If it isn't the anomaly in flesh and bone.

Arthur: So, to what purpose do the Empress herself come here. Just to meet this humble Admiral in his post?

Empress: *curious* You know my identity.

Arthur: I know a lot about your kind, and I have my own ways of acquiring such info.

Empress: You speak to me undaunted, but with no hint of hate or anger. Truly, an anomaly.

Arthur: Don't say something twice. You're here for the cube, aren't you?

Empress: I assume you are not going to hand it to me and probably saying: "I won't go down without a fight.". Well then, how are you going to possibly stop me without any ships around?

Viktoriya: You are going to fight me.

Arthur: Who says I'm going to stop you?

Empress/Viktoriya: Eh? Beg your pardon?

Arthur: You heard me. Just take it. Not like I can stop you.

Empress: Very well. I hope you are prepared to face impending doom, anomaly, or else you will regret your decision dearly. The climax...has started *leaves*

Arthur: Viktoriya, no Arbiter I: Titan. Hear my order: Rouse "it" from slumber. The Sirens will not know what hit them.

Viktoriya: Will do, Sir Admiral.

Arthur: And I figured you are itching to use "it" very much, yes?

Viktoriya: *smirks* You are correct, Master. 

Arthur: Then better use "it" in the most spectacular way possible.

Empress: Purifier, return to base.

Purifier withdrew all forces from the battlefield, baffling the forces of Azur Lane. As they returned to the office, they learned from the Admiral that the leader of the Sirens herself stole the cube from his hands. Being flashbanged, he was unable to react in time.

Later in the day, Elizabeth (Shtorm) came to his room.

Elizabeth: You lied. No way someone that powerful like you would be hindered by a flashbang. You must have let her go.

Arthur: Yes.

Elizabeth: I'm going to ask why, because knowing you, you must have a countermeasure to Orochi already.

Arthur: Do you remember "it"?

Elizabeth: Wouldn't it be overkill?

Arthur: With a floating fortress on our asses, I think not.

Inside the hidden Siren base:

Empress: Ready the Orochi. I want to see if humanity have any trick upon its sleeve or not.

In the cavern which Orochi resides, Prinz Eugen was seen looking at the slumbering metal hulk. She saw Kaga, from below, on top of Orochi's upper deck, with an emotionless expression on the face.

Kaga: Nee-sama, I'm on my way.

Red lines of light courses through the superbattleship, and the cavern rumbles over its awakening. The tremors could be felt over the entire naval base of Kure, causing all present ships to raise caution. They ran to the dockyard, only to see Orochi slipped from its moorings in shock and horror.

In a subterranean building below the Mariana Trench:

????: "Control system: Operational. Blast weaponry: Operational. Range weaponry: Loaded. Melee weaponry: Operation. All motive units ready"

????/Arbiter I - Titan: 

MECHAGODZILLA MARK 2 IS READY FOR WAR. 

The Titan surfaced not long after. With the upper half of the body above water, it raised its neck, its mouth wide open. A booming, thunderous roar echoed for miles away, then Mechagodzilla, with Arbiter I in helm, sets course towards Pearl Harbor.

(A/N: In short, Hornet and her team really didn't hallucinate)

https://youtu.be/-EifpM1NFGM

Specifications of Mechagodzilla Mark 2:

Length: 200 meters

Weight: 185 thousand tons.

Weaponry:

Four shoulder-mounted 356 mm railguns

40 missile launchers in 4 shoulder-mounted launch platforms

2 plasma cannons

2 hidden, side-mounted ballistic missile launcher

2 dorsal-mounted anti-gravity engines

Melee weaponry: Similar to original Mechagodzilla (jaws included)