The following is a list of characters and tropes that apply to them in Manga/ArpeggioOfBlueSteel. Do note that TheOtherDarrin is in full effect, as the drama CD and anime uses an entirely different set of voice actors. Note that due to the anime diverging from the manga's storyline, some characters' anime versions may differ from their manga counterparts.


!Blue Steel

The main characters. On paper a semi-independent [[Main/PrivateMilitaryContractors firm]] that also did some work for the Japanese government, at the beginning of the series Blue Steel is the only force that has a real chance at striking back against the Fog Fleet blockade of the Japanese islands. They are eventually hired by the Central government to deliver the blueprint of a weapon that might finally turn the tide in humanity's war against the Fog, to the only country likely still capable of producing it in the numbers needed: the United States of America.

Commanded by Gunzou Chihaya, and manned by some of his classmates from the Maritime Institute, Blue Steel's ability to fight the Fog Fleet on somewhat even terms is mostly due to the fact that it has its own Fog ship under its disposal: the renegade Fog submarine I-401, Iona, who follows Gunzou for reasons even she ''herself'' isn't quite sure of.

[[spoiler:Initially just composed of Iona, Blue Steel becomes an actual ''fleet'' once Takao throws in her lot with them, and Hyuuga joins the crew]].

[[folder:Members of Blue Steel]]

!!Gunzou Chihaya
->Voiced by: Creator/JunFukuyama (Drama CD), Creator/KazuyukiOkitsu (Anime)

The Captain of I-401, and he makes most of the tactical decisions of Blue Fleet in general.

* BadassInANiceSuit: He generally wears a primarily black suit and red tie after becoming the captain of the Blue Steel.
* TheCaptain
* ChickMagnet: Both human girls and Fog ships seem to be attracted to him, though perhaps for different reasons.
* ChildProdigy: He was one of the top students in his class back when he was studying to join the navy.
* CombatPragmatist: He's willing to do whatever it takes to win a battle. Considering his opponents are nigh-invulnerable who gave humans a CurbStompBattle countless times before, it's not surprising he's forced to think outside the box a little bit with I-401.
* DesperatelyLookingForAPurposeInLife: The revelation that his father was a traitor and witnessing his childhood friend Amaha Kotono died in a fire causes him to become this until he meet Iona.
* DisappearedDad: His dad, a war hero who captured the I-401 during the final naval battle between the UN Fleet against the Fog Fleet, was presumed dead after he and his crew first mission on the I-401 disappear after the submarine returned to Japan without it's crew. However, two years before the series began, Gunzou learns not only is his father and his crew alive but they defected to the Fog Fleet.
* {{Expy}}: With his good looks, daring strategic mind, and [[Creator/JunFukuyama identical voice]] (not to mention possessing a MysteriousWaif MacGuffinGirl), drawing comparisons between Gunzou and [[Anime/CodeGeass Lelouch]] is practically inevitable.
* IntelligenceEqualsIsolation: At first, during the academy
* TheParagonAlwaysRebels: While not exactly top of the class, he qualifies for this in the merit of being in the top three and is quite a decent captain even amongst professional soldiers. End result? Deserted the military, taking a few of their most talented personnel, and works as a mercenary.
* TheStrategist: He comes up with some rather unique tactics during combat to win against his opponents.
* RedBaron: Called the "Battleship Killer" and "Route Holder" in chapter one.

->Voiced by: Creator/AoiYuuki (Drama CD), Creator/MaiFuchigami (Anime)

A Fog ship somehow captured by humans a while back. While her origins are undoubtedly of the Fog fleet, she has no idea what her purpose was, other than to find and obey Gunzou Chihaya.
* AdaptationDyeJob: She has white hair in the manga, while it has more of a blueish tint to it in the anime.
* AmnesiacHero: She only remembers one order, which was to obey Gunzou Chihaya. This served extremely useful for the humans, who are finally able to fight back against the Fog ships for the first time since their appearance.
* {{Badass}}: While she doesn't appear to be one at first glance, she is a pretty effective fighter with the help of Gunzou and the other humans. ''How'' this badassery is shown varies depending on the media -- the anime mostly focuses on the ''physical'' abilities of her Mental Model (more or less taking over Haruna's role during the assault on the Okasabe mansion), while the manga focuses on her leadership and abilities as a strategist (as evidenced by her taking command of Blue Fleet against Hiei and her escorts while Gunzou and Hyuuga were away).
* CharacterExaggeration: In the anime, Iona is much more of an EmotionlessGirl, and angsts much more about her status as a Fog vessel.
* CoolBoat
* DetachedSleeves
* EmotionlessGirl: She's very stoic and calm and rarely shows strong emotions. The anime makes her even more emotionless.
* LittleMissSnarker: Iona in the manga has a pronounced and sometimes downright sarcastic sense of humor, particularly with Hyuuga.
* IAmWho: In both the anime and the manga, there are enough hints that Iona ''isn't'' simply a rogue Fog submarine, though both differ in the details: [[spoiler:the anime points to Iona being an avatar of the Admiralty Code, the architect of the Fog Fleet, while the manga instead hints that she's the Joint Tactical Network itself.]]
* MyMasterRightOrWrong: Despite being a Fog ship, she only remembers one order, to obey Gunzou. This brings a lot of conflict to other Fog ships she ends up fighting, most of all Kongou.
* MysticalWhiteHair: She has white hair, which hints at her being a Fog ship.
* RapunzelHair: She has waist length hair.
* ReiAyanamiExpy: An EmotionlessGirl with white hair and pale skin who is actually the Mental Model of a Fog Ship. This is even more emphasized in the anime, where she's even more emotionless and has blueish hair.
* ScrewTheRulesImDoingWhatsRight: [[spoiler:In episode 10, after suffering from a surprise attack from I-400 and I-402, I-401 begins to break down from sinking into the ocean. Gunzou orders her to gradually cut power to parts of the ship, and eventually orders her to cut off life support functions to preserve her remaining energy. Although she usually follows his orders without question, in this instance she became very conflicted about whether to save him, or let him die and continue the mission of getting the vibration torpedoes to America. So she instead decides to jettison her core and himself in a life pod in an attempt to hold out a bit longer, and fortunately for her, Takao finds them and gives up her nanomaterials to ensure both of them survive.]]
* SelfDuplication: She has one main form and several numbered clones running around the submarine, taking care of various tasks.
* SkirtOverSlacks: In her usual outfit
* SpaceshipGirl
* TheStoic
* SugarAndIcePersonality
* TalkingToHerself: With her other triplet sisters in the drama CD. In the anime each of the 400-series subs has their own voice actress.
* UndyingLoyalty: In episode 10 of ''Ars Nova'', she's very conflicted with Gunzou's order to leave him to his fate to save herself and the weapon plans. So she takes a risk in scuttling the remainder of her ship, and jettisoning him in a life pod with her core inside of it. Fortunately Takao finds them shortly afterwards and sacrifices her ship and nanomaterials in order to allow Iona to rescue Gunzou.

!!Sou Oribe
->Voiced by: Creator/TomokazuSugita (Drama CD), Shinobu Matsumoto (Anime)

The First Mate of I-401, Sou generally provides inventory of their supplies as well as aiding Gunzou with tactical decisions.

* CoolMask
* TheBlank
* TheFaceless: Always has his helmet on. He claims it's easier to contain his allergies this way.
* TheGraphShowsTheTrend: He loves them.

!!Kyouhei Kashihara
->Voiced by: Creator/MinoruShiraishi (Drama CD), Eiji Miyashita (Anime)

Weapons officer of I-401, Kyouhei is generally most active when they are fighting an enemy.

* CoolShades
* TheGenericGuy: Compared to the others, at least. All of the human officers who came from the nautical school belongs to the top ten of their class with the sole exception of Kyouhei, who ranks consistently... ''in the 200's.''
* {{Otaku}}: A mild case, since only him and Iona watch anime aboard the ship.

!!Iori Watanuki
->Voiced by: Creator/AkiToyosaki (Drama CD), Minami Tsuda (Anime)

The Engineer of I-401, she does humanly-possible maintenance aboard the ship.

* CuddleBug: Is sometimes seeing hugging Iona or her mini metal models.
* {{Gainaxing}}: Occasionally.
* GirlishPigtails
* WrenchWench: Comes with being the engineer.

!!Shizuka Houzumi
->Voiced by: Creator/NaoTouyama

The sonar operator of I-401, she plays the crucial role of locating various hazards outside the sub via sonar.

* BewareTheNiceOnes: Oh hell yes.[[spoiler: Who would have ''ever'' thought that she is skilled in '''''guerrilla warfare''''' prior to the Iwojima invasion arc?!]]
* HimeCut
* {{Meganekko}}
* MysteriousPast: [[spoiler: Apart that she was Maruri Hibiki replacement, her past is still a mystery.]]
* TheQuietOne

->Voiced by: Creator/RinaSato (Drama CD), Creator/ManamiNumakura (Anime)

Heavy Cruiser of the Fleet of Fog, she is the first named Fog ship Blue Steel battles and defeats (though chronologically speaking that honor would go to Hyuuga) in the series. When she is surprisingly let go by Gunzou in the wake of that battle, she develops a girlish fixation on Blue Steel's commander and, by extension, Humanity in general, to the point where she literally goes AWOL from the Fog Fleet.

Takao herself is the main character of the manga spinoff '''Salty Road''', which focuses on what she's been up to at Yokosuka, along with her minders Zuikaku and I-402.
* CanNotSpitItOut: Attempted to make a love confession to Gunzou... and failed miserably.
* CombatPragmatist: Something she learned from Gunzou
* HeelFaceTurn: Runs away from the Fog and joins Blue Steel.
* HeroicSacrifice: Anime-only: [[spoiler:She uses the remainder of her nanomaterials to restore Iona back into working order, though she loses her ship and her Mental Body in doing so. However, her core survived, and she is still able to at least turn up in screens onboard the ship.]]
** [[spoiler: Averted: Her mental model is fully restored during the last episode episode credits.]]
* InSeriesNickname: Tsundere Heavy Cruiser. Sees regular use by the Yamato-aligned Fog Ships like I-402 and Zuikaku.
* InstantCosplaySurprise: When she's on the Yamato she's subjected to several changes in a row.
* IWantMyBelovedToBeHappy: [[spoiler:In episode 10 of the anime, she sacrifices her ship and mental model after she locates the remains of I-401, and a barely alive Gunzou inside a lifepod with Iona's core inside.]]
* MacrossMissileMassacre: Deals one and takes one.
* RapunzelHair: Though it is not directly visible because her ponytail is usually put in an odd way
* RedAndBlackAndEvilAllOver: She's the series StarterVillain, and her ship's sinister red-and-black colour scheme means she looks the part, but she promptly performs a HighHeelFaceTurn and turns blue.
* ShesGotLegs: More prominently displayed in some of the [[ anime artwork.]]
* StalkerWithACrush: To Gunzou.
* StarterVillain: She's the first Fog warship the I-401 has a proper on-screen battle against. [[HighHeelFaceTurn The 'villain' bit doesn't last long, though.]]
* ThemedAliases: The surnames that Takao used during her forays into human society reflect the aliegances she had at that point: '''Kirino''' (literally "of the Fog") after the first time she was defeated by Gunzo, and '''Aoki''' (can be read as "pure blue") after she had fully aligned herself with Gunzou and Iona's Blue Fleet.
* {{Tsundere}}: She's a Sweet type, which is acknowledged by most characters. She'll be gentle and nice but '''do not''' make fun of her.
* SelfDuplication: Like Iona, she too has several mini models that helps her in doing mundane tasks.
* UnlimitedWardrobe: Like all mental models, she can change clothes as she wishes, but she's one of few who doesn't stick to one set.
* YouGottaHaveBlueHair: She has blue hair.

->Voiced by: Creator/SakiFujita (Anime)

[[spoiler:Former Fog battleship and flagship of the Second Oriental Fleet turned port operator]]
* CatSmile
* ExcuseMeWhileIMultitask: Her schtick. Apparently, she can [[spoiler:fend off rockets while talking to Kongo across Iwo Jima and]] talk to Makie while fighting Takao for [[ItMakesSenseInContext food]].
* GadgeteerGenius: For one thing, she built an army of robots, after extracting the raw materials from the Earth herself, since she didn't want to use nanomaterials.
* GenkiGirl: Acts this way towards Iona frequently.
* TheGlomp: She loves doing this to Iona.
* HighClassGlass
* LoveAtFirstPunch: With 12 corrosive torpedoes.
* PowerFist: Chapter 34 of the manga gives her a '''huge''' one which is bigger than her head.
* RocketPunch
* StalkerWithACrush: To Iona.
* ShipperOnDeck: To Gunzou and [[spoiler: Takao]] [[JustForPun ship]]. Mostly because she wants Gunzou away from Iona so she get have her herself.


!The Fleet of Fog (Japan)

The segment of the Fog Fleet blockading the Japanese islands, the Mental Models of its ships are the ones that Blue Fleet and its allies mostly interact with, via opposition (in Kongou's case) or actual dialogue (in the case of Haruna and Kirishima). Ostensibly under the command of Superbattleship Yamato, the responsibility for actually maintaining the blockade falls under Battleship Kongou, the latter of whom takes her duties ''very'' seriously.

[[spoiler:As of the current chapters, the Fog Fleet had broken up into factions, with Yamato and her subordinates (who are interested in Humanity, and thus are willing to let Iona continue on her own) on one side, and Kongou and her subordinates (who more or less want Iona dead) on the other.]]

[[folder:Members of the Japanese Fog Fleet]]


Supreme Flagship of the Fleet of Fog, and chronologically the first among the Japanese Fog Fleet to gain a Mental Model. It is apparently through her machinations that the rest of the ships blockading Japan gain their mental models. Disappeared without a trace during the Great Naval Battle years before, before making an unexpected return to the fleet two years before the start of the story.

[[spoiler:As Hyuuga and Takao soon discover, Yamato's mental models look ''exactly'' like Kotono Amaha, Gunzou's childhood friend, who was believed to have died two years prior.]] This casts her keen interest on Humanity in general, and the activities of Iona and her crew in particular, in an altogether new light, especially since (in the manga anyway), it was Yamato herself that "suggested" to Iona to seek Gunzou out.
* MysteriousBacker: Not that Gunzo and his crew are any wiser, but Yamato is this to them, to the point where she assigns Yukikaze to keep an eye on Iona, discretely of course.
* TheOjou
* PerpetualSmiler
* SingleMindedTwins: Averted. Unlike Nagato, Yamato's two Mental Models display distinct personalities, with one still acting like prim and proper princess, and the other... [[spoiler:acting exactly like Gunzou's dead childhood friend Kotono Amaha]].
* WorthyOpponent: Respects humanity due to their strategic skills and will to keep fighting the Fleet of Fog despite the odds.

->Voiced by: Creator/HoukoKuwashima (Drama CD), Creator/{{Yukana}} (Anime)

Flagship of the Second Oriental Fleet (before reorganization Third Oriental Fleet)
* EmotionlessGirl: Is this, and believes that all Fog ships should be this.
--> "We are weapons. Weapons have no need of emotions."
* EstablishingCharacterMoment: In the prologue for Episode One of the anime, a bit of the Last Great Battle is shown. In it, Kongo is shown at the head of the line (distinguished by her purple glow), and engages the human ships via [[RammingAlwaysWorks ramming]] them, hinting at the brute force method of solving problems she will exhibit later on.
* GracefulLadiesLikePurple
** PurpleIsPowerful
* ImplacableWoman: She becomes extremely obsessed with Iona and attempts to sink her at all costs.
* IronLady
* [[LickedByTheDog Liked by the Birds]]
* MidseasonUpgrade: In the manga. She gains access to Flagship Equipment care of Akashi, which aside from giving her a nice new gown and hat, turns her into a one-woman ZergRush: she is able to "transport" Fog Vessels from other parts of the Japanese archipelago to her location, giving them new bodies to transfer their cores to. In essence, a battleship-sized 3D printer.
* MyMasterRightOrWrong: While she dislike Yamato's idea that the Fleet of Fog should have Mental Models and humans to help them in their goals, she nevertheless obeys Yamato.
* RedEyesTakeWarning
* TheStrategist
* TheStoic
* ShesGotLegs
* [[spoiler:VillainousBreakdown: She gradually starts to act in ways that causes I-400 and I-402 to question her loyalty. Then in episode 10 of the anime, her ship is locked down by the two subs, and she also finds out that Maya, her last friend/ally, was an AI construct designed to spy on her.]]

Flagship of the First Oriental Fleet
* FinishingEachOthersSentences: Her two mental models do this.
* SingleMindedTwins: She seems to have a pair of mental models as her avatar.
* YamatoNadeshiko: There seems to be a pattern to these battleships...

Battleship of the Fleet of Fog.
* BadassLongcoat: A rather intimidating AllEncompassingMantle variant. Its badassery is acknowledged in-universe as well - wearing it gives Haruna a significant confidence-boost. [[spoiler: Not really. Supplemental material in the manga reveals that the coat actually boosts her processing power by 100%. Losing it drastically reduces her capabilities.]]
* CoatCape: It covers her entire body, and most of the time only the upper part of her head is visible.
* ChickMagnet: She attracts Makie and Maya very naturally.
* CryCute: When her coat is taken away, and when conseling with Makie.
* GirlishPigtails
* HeelFaceTurn: Saving Makie definitely counts, though she does not want to join Blue Steel.
* HiddenHeartOfGold: She might seem stoic, though she does not hesitate when Kirishima or Makie is in danger.
* LargeHam
-->''(after putting on her cape and striking a pose)'' "Ka-CHING!"
* OneManArmy: She goes VideoGame/DynastyWarriors style on invading human soldiers and vehicles when Makie is threatened.
* SleepCute
* RedOniBlueOni: Blue to Kirishima's red.
* InstantCosplaySurprise: By Makie.
* TheStoic: Most of the time, especially when her mouth is covered by the collar of her coat.
** NotSoStoic: Without her coat, or if her mouth is visible. Then not even the coat can hide her emotion when Doctor Okabe died.
* TookALevelInBadAss: After losing her ship body.

Battleship of the Fleet of Fog.
* BadassLongcoat: In the manga.
* ButtMonkey: Poor Kirishima often gets the short end of jokes as Yotarou the stuffed bear.
* ExpressiveMask: Often, as Yotarou.
* FashionableAsymmetry: In the anime, though the design was first revealed on the cover of Book 4.
* {{Irony}}: Prior to her battle with the I-401 (and the ''Hakugei'' in the manga), she sneers at the idea of regret and humans expressing it. Guess what happens after her defeat at their hands...
* JerkAss: Before losing her ship.
* LargeHam
* PintsizedPowerhouse: After being reconstructed with part of Haruna's nanomachines and gaining control of one of Makie's stuffed dolls. Even in this form she can still knock out soldiers with ease. [[spoiler: In the manga, the stuffed doll is actually a costume the now chibified Kirishima wears.]]
* {{Pride}}: A traits of hers and what led to her downfall. Haruna and Kirishima could have defeated both the I-401 and Hakugei had they call the rest of the 2nd Oriental Fleet for backup but refuses out of her desire to claim credit in defeating the I-401.

Battleship of the Fleet of Fog, leader of the governing body "Student Council".

* TheDragon: To Kongou.
* OrderVersusChaos: She believes the Fleet should be orderly and not chaotic which is why she hates Hyuga.
* StudentCouncilPresident: She and her own personal fleet wear Student council uniforms.
* TheRival: To Hyuga. Hiei doesn't like the former 2nd Fleet Flagship because her eccentric behavior rub off on Takao, Haruna, Kirishima and Maya, her subordinates at the time, which lead them to have their own personalities and later defecting from the Fog.

Battleship of the Fleet of Fog, and Hyuuga's twin sister.

* TheGhost


Heavy Cruiser of the Fleet of Fog, currently (chapter.50) under Haruna's command, and calls her "The Flagship of My Heart".
* AnnoyingYoungerSibling: To Kongou. Fortunately, Kongou is TheStoic.
* ButtMonkey: She gets easily hacked by the other Mental Models.
* DeathByAdaptation: In the ''Ars Nova'' anime. Her ship body is even absorbed into Kongou during the finale.
* ElegantGothicLolita
* GenkiGirl: Most of the time. [[spoiler:In Ars Nova, after the revelation that she's an AI construct designed to spy on Kongou, this attitude takes on a creepy undertone when she starts to repeat herself to Kongou.]]
* MoreDakka: It's clear that the Fog like to prefer this, but she likes to take this to a ''[[UpToEleven to a completely different level]]''.
-->It's a CARNIVAL! ''(shoots '''everything''')''
* PerkyFemaleMinion
* PluckyComicRelief
* SelfDuplication: Uses her mini models as an orchestra.

->Voiced by: Creator/AoiYuuki

Fleet of Fog submarine, member of the Intelligence Fleet. Looks exactly like Iona, save for her costume.
* DeathByAdaptation: Is sunk by Iona in the ''Ars Nova'' anime.
* {{Qipao}}: Wears one.
* TheStoic: What we seen about her so far.

->Voiced by: Creator/AoiYuuki

Fleet of Fog submarine, member of the Intelligence Fleet. Also looks exactly like Iona, save for her costume.

In the manga, she is the one that retrieves Takao in the wake of her battle against Zordan, and brings her to Yamato for a little heart-to-heart. Later on, she accompanies Takao and Zuikaku to Yokosuka, where she more or less settles into the role of Takao's nanny.

* DeathByAdaptation: See I-400's entry.
* HeelFaceDoorSlam: In the anime at least, she only start to show a tiny bit of emotion just before she got hit for shielding her sister.
* {{Troll}}: Enjoys teasing Takao over her crush on Gunzo.


A Fog "assault ship", she joins I-402 in infiltrating Yokosuka, and in the process becomes Takao's virtual roommate in their hideout at the docks. Unlike the various non Blue Steel-aligned Fog Mental Models introduced, Zuikaku shows none of the awkwardness in interacting with the local human population, and becomes sort of a regular at the local market due to the seafood she catches.
* KindHeartedCatLover: Is shown to have a cat as a pet, though fandom is divided at whether or not it's a real cat, or another mental model.
* NonIndicativeName: Zuikaku has been repeatedly called (in official materials no less!) as an "assault ship", but its obvious to all who can see that her ship body is an aircraft carrier.

[[folder:Japanese Government and Military]]

Current Prime Minister of the Central District of the three districts that the Fog's blockade has carved Japan into.

* NumberOne: Was formerly Kita's XO when he was in the JMSDF.
* FriendlyEnemy: Views Kita as this; while they're bitter political opponents, he still has affection for his former captain.
* ReasonableAuthorityFigure

!!Ryoukan Kita
Diet member and likely the next Prime Minister of the Central District.

* TheCaptain: Was formerly a JMSDF destroyer skipper, and acquainted with Gunzou's father.
* FriendlyEnemy: Views Mitsumine as this; while they're bitter political opponents, he still has affection for his former XO. That said, he's not as nice about it as Mitsumine is.

!!Kamikage Ryujirou

!!Cruz Herder
One of the United States Navy [=SEALs=] stationed in Japan before the fog blockade now part of the Unified Army.

!!Daisaku Komaki
Captain of Hakugei 3
* BadassNormal: with help from I-401 becomes the captain of the first man made ship to sink two Fog battleship

!!Maruri Hibiki
->Voiced by: Creator/KanaHanazawa

Former Sonar operator of I-401. Transfers to the ''Hakugei.'

* LoveCannotOvercome: Even though she was the first crew member to join the Blue Steel because she was in love with Gunzou, his many attempts that almost got him killed was just too much as she couldn't bear seeing him die.

!!Makoto "Osakabe"
Prime Minister of the Northern District and a Design Child.
* CreepyChild
* DudeLooksLikeALady
* TeamSwitzerland: Is willing to support either the Japanese government or the Fleet of Fog as long as Hokkaido benefits from the alliance.
* TheLeader: Was genetically engineered to be a capable leader without humans flaws like corruption or greed.

!The Scarlet Fleet

A splinter faction of the Fog Fleet maintaining the European blockade, and commanded by Gunzou's father Shouzou, the Scarlet Fleet has notably deviated from the duties tasked to it by the Admirality Code, to the point where it's been drawn into conflict with the ''rest'' of the European Fleet (under the HMS Hood). With the Superbattleship Musashi as its flagship, the fleet seems to be tacitly supporting Shouzou's machinations toward an as-of-yet unknown goal.

[[folder:Members of the Scarlet Fleet]]

!!Shouzou Chihaya
Captain of the Musashi, Former Captain of the I-401 before he defected to the Fleet of Fog
* CoolShades
* FaceHeelTurn: Was a former war hero who captured the I-401. Now he's one of the Fleet of Fog commanders.
* SchrodingersCast: While very much alive and even a major antagonist in the manga, Shouzou's fate is left ambiguous in the ''Ars Nova'' anime.
** OnlyMostlyDead: Previews for the second Ars Nova movie show that Shouzou is very much alive, and much like his manga counterpart, in command of Musashi.

Superbattleship of the Fleet of Fog, and sister ship of Yamato.
* EyesAlwaysShut
* PrettyInMink: Unlike her sister, she appears instead like a Russian Snow Girl.
** Averted in the Ars Nova Cadenza movie previews, where she's shown to be wearing a more revealing, and generally "hipper", outfit a teenaged-looking girl would be expected to wear.

Fleet of Fog submarine European Fleet.
* CryCute: When Zordan orders her to cancel her mental model.

!!Zordan Stark
Captain of U-2501.
* CombatPragmatist
* GermanicEfficiency: Does not like mental models because of their calculation usage. At one point, he even orders his own submarine to cancel her mental model because of it.
* SmugSnake

[[folder:Unaligned Fog Fleet Ships]]

The first Fog battleship sighted by humans.
* GirlishPigtails
* SingleMindedTwins

A fog battlecruiser that apparently defected due to a disagreement with the European Blockade fleet under the command of the Hood; while the latter advocated a more direct intervention against Shouzo's Scarlet Fleet, Repulse only wanted to continue with the Admiralty Code's initial order of blockading the sea lanes of Europe. When they came to blows, Repulse escaped into Pacific waters instead with her escort Vampire in tow.
* BroomstickQuarterstaff: She uses broomsticks to repair her damage.
* {{Meganekko}}
* {{Meido}}
* ScrewThisImOuttaHere

Repulse's escort destroyer, and one of the first Fog ships shown to have a personality ''before'' she was finally given a Mental Model (care of Repulse's annoyed replies). While she obviously doesn't have high opinions of her command ship's leadership capabilities, she's decided to stick with the hapless heavy cruiser in her exile to the Pacific.
* {{Meido}}: Much like her command ship, Vampire's Mental Model is themed as a Victorian Maid, though she wears a much shorter skirt, as well as a bat-themed ribbon.
* ServileSnarker: Vampire takes every opportunity to belittle Repulse's competency, but it's obvious that she's loyal to cruiser all the same.



!!Makie Osakabe

A young girl with some mysterious origins. Her role becomes much bigger after she runs into Haruna and Kirishima.

* ArtificialHuman
* ChildProdigy: Helped design the torpedo that has the Fog running scared.
* LittleMissBadass
* MoralityPet: Turned Haruna from a war machine into one of the best developed characters of the manga.
* MysteriousWaif: She isn't allowed to travel very far from the mansion she lives in. As a result, she hasn't had much contact with too many people.

!!Lawrence Valentine/Toujuurou Osakabe

Makie's overprotective butler. Unknown to Makie, Lawrence is actually [[spoiler:Toujuurou Osakabe, her grandfather and creator.]]

In Ars Nova, he is Makie's adopted father and a prominent weapons researcher. [[spoiler:His attempts to defeat the Fog inevitably turns up in failure, largely due to the limitations of humans. He ends up creating Makie in the lab, and with her help, manages to design a torpedo that's capable of defeating Fog ships.]]

* TheAtoner
* BattleButler: Although Makie just knows him as Lawrence, secretly he is...
*** [[spoiler: TheProfessor: Involved in the creation of Makie and the other Design Children and her unseen 'grandfather'.]]
* DiseaseBleach:[[spoiler: His hair turned white as he watched most of design children die in front of him.]]
* [[spoiler:FakingTheDead: In Ars Nova, he faked his death in an attempt to keep the government from doing things to Makie. While Makie believed he really died, Haruna and Kirishima finds out he was still alive, but bedridden. He does [[KilledOffForReal eventually die]] shortly after meeting the two Fog ship girls however, but not before asking them to watch over Makie, after noticing how attached the girl was to them.]]
* [[spoiler:OmnidisciplinaryScientist: In Ars Nova where he was a weapons researcher and geneticist. Unlike in the manga where he was only a geneticist.]]

!!Saori Chihaya
Mother of Gunzou Chihaya. She is currently under house arrest.

* DeathByAdaptation: Hinted to have committed suicide in the ''Ars Nova'' anime.
* GildedCage: She's place under house arrest at mansion that's heavily monitored by security cameras.
* ShipperOnDeck: Ships Takao with her son.

!!Kotono Amaha

The childhood friend of both Gunzo and Sou, she was the valedictorian of their class at the Maritime Institute. She died when the test facilities of the institute caught fire, but her remains have never been found. It was her death that fueled Gunzou's dissatisfaction with the current state of the world, which eventually made him join up Iona.

[[spoiler:There are increasing signs that she might have been one of Yamato's mental models to begin with, sent to live among humanity to satisfy whatever curiosity the supreme battleship had for humans in general.]]

* TheAce: Her reputation among Gunzo's schoolmates. Sou even calls her "the wall that Gunzou could not overcome".
* ChildhoodFriend: To Gunzou and Sou.
* CynicismCatalyst: Her death was the prime motivator for Gunzo to change the status quo of the world, and ally with Iona.
* PosthumousCharacter: Died in an accident two years prior to the start of the story, however...
** NeverFoundTheBody: ... they never found her body after the fire that killed her.