This is Captain Nemo of the Nautilus! I repeat! Tell us your name! That's right! Your name! The name you want to go by! Whatever name that is, it's okay! The battle for your name is also a battle for your sense of self! It's not easy by any means, but only you can fight it! Because what you gain from winning is the most precious thing of all!
—Nemo
Full title: "Great Void Sea Battle, Imaginary Scramble [To the Surface, Nautilus!]". Written by amphibian (of Raging Loop fame).
Several days after the reveal of Nemo's identity in the Indian Lostbelt, Sion's Servant is ready to launch the first expedition of the Nautilus with the protagonist on board into the Sea of Imaginary Numbers as preparation for their assault on the fifth Lostbelt. However, the mission quickly goes awry when an unexpected monster attacks the submarine and heavily damages several sectors. This is further complicated by the arrival of a mysterious Foreigner Servant claiming to be Van Gogh, who demonstrates bizarre and inexplicable powers that could be of use to Chaldea....
While the chapter was originally released as a limited event, it is important to the Myth Arc and was later made available as a Main Interlude.
Watch the trailer here
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Tropes found in this episode:
- All Just a Dream: Played with and zig-zagged. While the Nautilus crew are unaware of the fact until near the end, Da Vinci and Sion (and the player) become aware the whole event is a dream in the prologue, and the Flower Outer God's power means what happened in the event ultimately influences reality as well.
- Anachronic Order: Despite being released after the end of the fifth Lostbelt the story is an Interquel between it and the fourth Lostbelt.
- Arc Villain:
- The initial instigator is revealed to be the Flower Outer God, implied to be Vulthoom, who created Van Gogh and dragged the protagonists into the Imaginary Number Space to make an alliance with the Outer God of the Abyss. Defeating it is necessary to save Van Gogh.
- Yang Guifei then takes up the role following the Flower Outer God's defeat, corrupting many of Chaldea's Foreigners with the intent of having them fight it out for control of the Void Sea and thus which Outer God gets to rule the world in the coming era.
- Big Bad Ensemble: Three Outer Gods, each with their own Foreigner influencing events in their favor. It's the Flower Outer God who serves as the final opponent for the first part of the event.
- Can't Kill You, Still Need You: None of the hostile forces in the Imaginary Sea go all out to destroy the Nautilus because their creator is still on board, while the other Outer Gods need the crew as their only remaining source of eldritch power. That said, Chaldea is not aware of this until they're no longer needed.
- Central Theme: Identity. Most of the Servants either are "patchwork monsters" like Frankenstein and Meltryllis, have identity issues like Raikou, or in Nemo's case, is both since he's a Phantom Spirit merger who has further split his mind into the Nemo Series who are prone to infighting. In addition, Van Gogh suffers from an Identity Breakdown when she realizes she's actually Clytie in possession of Vincent's powers and memories. The climax of the chapter comes when Nemo who feels a connection to Van Gogh due to their shared circumstances tells her that she can forge her own identity, which she does by naming herself as Clytie van Gogh.
- Continuity Nod: Goredolf notes that he first saw MHXX when he was on his vacation in Hawaii, which was the third summer event that he cameoed in as "Aloha Man".
- Dangerous Forbidden Technique: Van Gogh's Noble Phantasm is a Reality Marble that allows her to become a Reality Warper through her paintings, but if anyone looks upon it while it's active they either go insane or (if they're a fellow Foreigner), get hopped up on eldritch power and become proper vessels for their Outer God patrons.
- Eldritch Location: Both versions of the Void Sea. Its original state is so alien that it's impossible for anything within to interact anything from real space, and vice-versa, effectively letting Chaldea treat it as though it were completely empty. Its modified state is composed of rainbows that shed no light, have the fluid dynamics of water, and either drive anyone who views it insane, or doing so drive the world insane, is inhabited with creatures that can only be discerned by layering illusions over their actual forms and can hide in gaps between spaces, and lacks a concept of depth.
- Flower Motif: Sunflowers are featured in various places throughout the event as foreshadowing for Van Gogh's true identity.
- Foregone Conclusion: The incident will be wrapped up with zero casualties and then forgotten about as revealed in the prologue for Atlantis.
- Gameplay and Story Integration: Unlike most of the others in the party Skadi doesn't have a swimsuit version available to her so she forces herself to be compatible with Scáthach's swimsuit. The one time you use her she's noticeably weaker than the other party members including having unleveled skills due to the incompatibility and she spends the rest of the story in a supporting role after noticing she's not able to do much in that state.
- The Heavy:
- Hokusai was called by Van Gogh to follow Chaldea into Void Space and then exposed to Van Gogh's Noble Phantasm which allowed her Outer God to brainwash and strengthen her. She then used her new power to create the imaginary sea and all the threats inside as a means of keeping Chaldea trapped there.
- After stopping the Evil God of Flowers, Yang Guifei in turn reveals she was sent by her own patron Outer God to take advantage of the aftermath, stealing Van Gogh's newly-created Holy Grail and corrupting several of Chaldea's Foreigners in order to start a winner-take-all death match for control of the Void Sea.
- Info Dump: Done by Caster Gilles to better explain what exactly the Foreigners Class and the Outer Gods are as well as their relationship with each other.
- Leaning on the Fourth Wall: The scenes with Da Vinci and Sion are filled with this as they both know that they are in a dream and believe that the only reason they are still active in it is that they have some purpose to fulfil in for the dreamer AKA the general audience. In this case, they're the ones who receive the information on Foreigners and Outer Gods from Gilles.
- Mundane Utility: Thanks to the protagonist not having to be conservative with Command Seal usage one of the most common uses of them is to get servants who were just summoned to quickly change into their swimsuit forms.
- The Mutiny:
- The Nemo Marines attempt to pull one of these off when it becomes clear that the protagonist will not kill Van Gogh no matter what threat she poses. Luckily Xiang Yu wakes up in the nick of time and suppresses it before it could get off the ground.
- Yang Guifei starts a second mutiny via brainwashed several members of the Nero Series with her dolls, allowing her to steal the Holy Grail and start the story's second arc.
- Remember the New Guy?: Upon Yang Guifei being summoned, one of the responses is to call her Yuyu, as well as the protagonist feeling like she's familiar somehow. This is a nod to the fact that ever since her debut she's been Out of Focus.
- Rewatch Bonus: After the reveal of Hokusai disguising herself as one of the Nemo Marines one can rewatch their introductory scene and notice that thirteen Nemo Marines are shown off in their group shot instead of the supposed twelve.
- Running Gag:
- Berserkers are continuously added to the Nautilus' crew, to Captain Nemo's chagrin.
- Van Gogh constantly cracking jokes, or "Van Goghks" and lampshading them.
- Spotting the Thread: Hokusai's disguise as one of the Nemo Marines was good enough to fool all the other Nemos with only two flaws causing it to be undone. The first is that as Nemo already specified the amount of Nemo Marines in the ship so an outside observer can notice that there's one more Nemo Marine than there should be (she gets around this by taking advantage of how there's almost never a time all the Marines get together in one place), and secondly is that all the Marines are supposed to be functionally identical so Hokusai being the only one of the Marines to modify the charm that Yang Guifei gave all of them was a huge red flag.
- Tempting Fate: The crisis kicks off just as all the eggheads state it's literally impossible for something to go wrong.
- Too Awesome to Use: Averted with Command Spells. The fact that the Nautilus has a magical furnace similar to Novum Chaldea means the protagonist can regenerate them on site, and they go through a whopping seven by the end of the event.
- You Cannot Grasp the True Form: Even in its interactable state, the Void Sea is utterly incomprehensible to human minds, with the rainbows that make up its 'waters' being nothing more than a hallucination.
