Characters: Arpeggio of Blue Steel

The following is a list of characters and tropes that apply to them in Arpeggio of Blue Steel. Do note that The Other Darrin 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' tropes will be a mix from either media.

    open/close all folders 

Blue Steel

The main characters. On paper an independent firm that also does 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 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.

Initially just composed of Iona, Blue Steel becomes a fleet once Hyuuga and Takao switch sides, but only Takao has a ship to contribute. In the Ars Nova anime Haruna and Kirishima also end up joining.

    Members of Blue Steel 

Gunzou Chihaya

Voiced by: Jun Fukuyama (Drama CD), Kazuyuki Okitsu (Anime)

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

  • Badass in a Nice Suit: He generally wears a primarily black suit and red shirt when meeting with clients. In Ars Nova he wears the suit all the time.
  • The Captain
  • Chick Magnet: Both human girls and Fog ships are attracted to him, though (probably) for different reasons.
  • Child Prodigy: He was one of the top students in his class back when he was studying to join the navy.
  • Combat Pragmatist: He's willing to do whatever it takes to win a battle. Considering his opponents are nigh-invulnerable warships who gave humans a Curb-Stomp Battle they still haven't recovered from, it's not surprising he's forced to think outside the box with I-401.
  • Desperately Looking for a Purpose in Life: The revelation that his father was a traitor and losing his childhood friend Amaha Kotono in a fire causes him to become this until he meets Iona.
  • Disappeared Dad: 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 leaving Japan in I-401 which later returned 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 identical voice (not to mention possessing a Mysterious Waif MacGuffin Girl), drawing comparisons between Gunzou and Lelouch is practically inevitable.
  • Intelligence Equals Isolation: At first, during the academy. He still has trouble relating to people but is surprisingly comfortable speaking with Fog Mental Models.
  • Oblivious to Love: It's doubtful that he had any idea he had two girls swooning over him during school. One still is, the other died in a terrible fire... maybe
  • Red Baron: Called the "Battleship Killer" and "Route Holder" in chapter one.
  • The Paragon Always Rebels: While not exactly top of the class, he qualifies for this in the merit of always being in the top three at school and is quite a decent captain even compared with those with more experience. End result? Deserted the military, taking a few of their most talented personnel with him, and starts work as a mercenary.
  • The Strategist: He comes up with some rather unique tactics during combat to win against his opponents.
  • Xanatos Speed Chess: Routinely changes plans on the fly based on new information or depending on how event play out. This ability is what makes Blue Steel, and himself in particular, such a threat to the Fleet of Fog.

Iona/I-401

Voiced by: Aoi Yuuki (Drama CD), Mai Fuchigami (Anime)

A Fog ship somehow captured by humans in the Great Naval Battle seventeen years ago. 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.
  • Adaptation Dye-Job: She has white hair in the manga, while it has more of a blueish tint to it in the anime.
  • Amnesiac Hero: 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).
  • Barbie Doll Anatomy: During her introduction to Gunzou in the manga, Iona pretty much featured this during her Naked First Impression. Justified as we see her part-way through forming her body and the only part that's finished is her face.
  • Character Exaggeration: In the anime, Iona is much more of an Emotionless Girl, and angsts much more about her status as a Fog vessel.
  • Cool Boat
  • Detached Sleeves: Her default outfit in Ars Nova. She's fond of casual t-shirts and shorts in the manga.
  • Emotionless Girl: She's very stoic and calm and rarely shows strong emotions. The anime makes her even more emotionless.
  • Little Miss Snarker: Iona in the manga has a pronounced and sometimes downright sarcastic sense of humor, particularly with Hyuuga.
  • I Am Who?: 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: 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.
  • My Master, Right or Wrong: 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.
  • Mystical White Hair: She has white hair, which hints at her being a Fog ship.
  • Rapunzel Hair: She has waist length hair.
  • Rei Ayanami Expy: An Emotionless Girl 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.
  • Screw the Rules, I'm Doing What's Right: 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.
  • Self-Duplication: She has one main form and several numbered clones running around the submarine, taking care of various tasks.
  • Skirt over Slacks: In her usual outfit
  • Spaceship Girl
  • The Stoic
  • Sugar and Ice Personality
  • Talking To Herself: With her other triplet sisters in the drama CD. In the anime each of the 400-series subs has their own voice actress.
  • Undying Loyalty: 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: Tomokazu Sugita (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.

Kyouhei Kashihara

Voiced by: Minoru Shiraishi (Drama CD), Eiji Miyashita (Anime)

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

  • Big Eater: Not so much in quantity as frequency: it's a common sight to see him eating some kind of snack while others are talking. He's even got a cooler installed at his workstation!
  • Cool Shades
  • The Generic Guy: 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. He ranked in top 5 in weapons training though, so his position in the crew is justified.
  • Hidden Depths: He might be a goofball weapons specialist, but there's been hints that Kyohei is a bit of a history nut.
  • Hot-Blooded
  • Otaku: A mild case, since only him and Iona watch anime aboard the ship.

Iori Watanuki

Voiced by: Aki Toyosaki (Drama CD), Minami Tsuda (Anime)

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

Shizuka Houzumi

Voiced by: Nao Touyama

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

Takao

Voiced by: Rina Sato (Drama CD), Manami Numakura (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.
  • Can Not Spit It Out: Attempted to make a love confession to Gunzou... and failed miserably.
  • Combat Pragmatist: Something she learned from Gunzou
  • Heel-Face Turn: Runs away from the Fog and joins Blue Steel.
  • Heroic Sacrifice: Anime-only: 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.
    • Averted: Her core survived and she is still able to at least turn up on screens or as projections on board the ship. Her mental model is fully restored during the last episode episode credits.
  • In-Series Nickname: Tsundere Heavy Cruiser. Sees regular use by the Yamato-aligned Fog Ships like I-402 and Zuikaku.
  • Instant Cosplay Surprise: Is on the receiving end of several rapid-fire costume changes courtesy of Yamato. Notable in that the switches really are instant, illustrating just how out of her league Takao is against Yamato.
  • I Want My Beloved to Be Happy: 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.
  • Macross Missile Massacre: Deals one and takes one.
  • Rapunzel Hair: Though it is not directly visible because her ponytail is usually put up in a complex corkscrew.
  • Red and Black and Evil All Over: She's the series Starter Villain, and her ship's sinister red-and-black colour scheme means she looks the part, but she promptly performs a High Heel-Face Turn and turns blue.
  • She's Got Legs: More prominently displayed in some of the anime artwork.
  • Stalker with a Crush: To Gunzou.
  • Starter Villain: She's the first Fog warship the I-401 has a proper on-screen battle against. The 'villain' bit doesn't last long, though.
  • Themed Aliases: 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.
  • Self-Duplication: Like Iona, she too has several mini models that helps her in doing mundane tasks.
  • Unlimited Wardrobe: Like all mental models, she can change clothes as she wishes, but she's one of few who doesn't stick to one set.
  • You Gotta Have Blue Hair: She has blue hair.

Hyuuga

Voiced by: Saki Fujita (Anime)

Former flagship of the Fleet of Fog Second Oriental Fleet. Sunk by Blue Steel before the events of the series and took up a job as port operator on Iwo Jima

The Fleet of Fog (Japan)

The segment of the Fog Fleet blockading the Japanese islands, the Mental Models of its ships are the only ones the audience has met so far. Ostensibly under the direct command of Superbattleship Yamato, the responsibility for actually maintaining the blockade falls under Flagships Nagato (First Fleet) and Kongou (Second Fleet).

As the series progresses, the Fleet of Fog is starting to fracture over ideologies and interpretations of their orders. Musashi has formed a sub-fleet with human crews in Europe; Hood is collecting support from her subordinates to oppose Musashi as violating the Admiralty Code; Kongou is getting fed up with humanity's recent successes while Nagato seems more interested in playing both sides For the Lulz. Meanwhile Yamato is planning something.

    Members of the Japanese Fog Fleet 

Yamato

Supreme Flagship of the Fleet of Fog, and chronologically the first among the Japanese Fog Fleet to gain a Mental Model. Disappeared without a trace during the Great Naval Battle seventeen years ago, made an unexpected return to the fleet two years before the start of the story with a Mental Model. It was her decision for other Fog warships to generate Mental Models as well.

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.
  • Mysterious Backer: 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.
  • Perpetual Smiler
  • Single-Minded Twins: Averted. Unlike Nagato, Yamato's two Mental Models display distinct personalities, with one still acting like prim and proper princess, and the other... acting exactly like Gunzou's dead childhood friend Kotono Amaha.
  • The Chessmaster: Yamato is planning something. She's not saying what that something is, but she's been encouraging select subordinates to spend time learning about humans.
  • The Ojou
  • Orcus on His Throne: Yamato has yet to do much of anything all series save for pointing people where she wants them to go. You just know that when she's ready to make her plans known, it's going to be big.
  • Troll: In the very non-canon extras included in each manga volume, Yamato takes particular pleasure in trolling her subordinates I-400 and I-402.
  • Worthy Opponent: Respects humanity due to their strategic skills and will to keep fighting the Fleet of Fog despite the odds.

Kongou

Voiced by: Houko Kuwashima (Drama CD), Yukana (Anime)

Flagship of the Second Oriental Fleet (Third Oriental Fleet before reorganization)
  • Emotionless Girl: Is this, and believes that all Fog ships should be this. Downplayed in the manga where she's more The Stoic.
    "We are weapons. Weapons have no need of emotions."
  • Establishing Character Moment: 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 ramming them, hinting at the brute force method of solving problems she will exhibit later on.
  • Graceful Ladies Like Purple
  • Implacable Woman: She becomes extremely obsessed with Iona and attempts to sink her at all costs.
  • Iron Lady
  • Liked by the Birds
  • Midseason Upgrade: 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 Zerg Rush: 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.
  • My Master, Right or Wrong: 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.
  • Red Eyes, Take Warning
  • The Strategist
  • The Stoic
  • Took a Level in Badass: In her early appearances Kongou seemed almost lazy, content to keep the status quo and watch the seabirds. After losing at least five ships note  to Iona and crew, Kongou has finally had enough and is going all out. Cue her Mid-Season Upgrade and the summoning of her entire fleet with the express purpose of sinking Iona.
  • She's Got Legs: The art rarely misses an opportunity to show them off.
  • Villainous Breakdown: 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.

Haruna

Battleship of the Fleet of Fog.
  • Badass Longcoat: A rather intimidating All-Encompassing Mantle variant. Its badassery is acknowledged in-universe as well - wearing it gives Haruna a significant confidence-boost. note 
  • Coat Cape: It covers her entire body, and most of the time only the upper part of her head is visible.
  • Chick Magnet: She attracts Makie and Maya very naturally.
  • Cry Cute: When her coat is taken away, and when conseling with Makie.
  • Defrosting Ice Queen: She's gone from borderline Emotionless Girl to simply The Quiet One. Time will tell if she softens to anyone but Makie or Kirishima, but now that she's joined the naval academy (undercover) she's not even wearing her coat!
  • Girlish Pigtails
  • Heel-Face Turn: Saving Makie definitely counts, though she does not want to join Blue Steel.
  • Hidden Heart of Gold: She might seem stoic, though she does not hesitate when Kirishima or Makie is in danger.
  • Mama Bear: Woe betide those who would harm Makie. Her destruction of an entire army division with armored support was holding back.
  • One-Man Army: She goes Dynasty Warriors style on invading human soldiers and vehicles when Makie is threatened.
  • Sleep Cute
  • Red Oni, Blue Oni: Blue to Kirishima's red.
  • Instant Cosplay Surprise: By Makie.
  • The Stoic: Most of the time, especially when her mouth is covered by the collar of her coat.
    • Not So Stoic: Without her coat, or if her mouth is visible. Not even the coat could hide her emotion when Doctor Osakabe died.
  • Took A Level In Bad Ass: After losing her ship body.
  • Villainous Breakdown: Professor Osakabe's death sends Haruna's emotions into a destructive feedback loop. She very nearly launches an annihilation attack on all three Japanese capitals before the Admiralty Code steps in.

Kirishima

Battleship of the Fleet of Fog.
  • Badass Longcoat: In the manga.
  • Bare Your Midriff: Her original, post-sinking outfit in the manga was a Badass Longcoat and matching business suit which only buttoned from the collar to her sternum, leaving her midriff in full view. Her outfit in the anime, despite being more revealing elsewhere, only had a thin strip of skin showing between her trousers and shirt top.
  • Butt Monkey: Poor Kirishima often gets the short end of jokes as Yotarou the stuffed bear.
  • Expressive Mask: Often, as Yotarou.
  • Fashionable Asymmetry: 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...
  • Jerk Ass: Before losing her ship.
  • Jerk with a Heart of Gold: The Humiliation Conga of getting sunk and getting reconstituted as a stuffed bear has mellowed her out. She's been ready to be the fall-guy when trying to explain things with Kongo and puts considerable stock in loyalty.
  • Large Ham
  • Pintsized Powerhouse: 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. 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.

Maya

Heavy Cruiser of the Fleet of Fog, currently (chapter.50) under Haruna's command, and calls her "The Flagship of My Heart".

Hiei

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

  • The Dragon: To Kongou.
  • Order Versus Chaos: She believes the Fleet should be orderly and not chaotic which is why she hates Hyuga.
  • Roboteching: Hiei's "Sniper System" lets her bend the beam of her Wave Motion Gun significantly off-axis. The system is apparently unique to her.
  • Student Council President: She and her own personal squadron wear matching Student council uniforms.
  • The Rival: To Hyuuga. Hiei doesn't like the former 2nd Fleet Flagship because her eccentric behavior rubbed 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.
  • Zettai Ryouiki: A solid Type A.

Myoukou

Heavy Cruiser and Hiei's second-in-command of the "Student Council".

  • BFG: Her Super-Gravity Cannon takes the form of a pair of colossal gun barrels longer than her own hull.
  • Cold Sniper
  • Eyepatch of Power: Linked to her main cannons as a targeting display, it's otherwise decorative and removable.
  • Fashionable Asymmetry: Her knee-socks are of different lengths. She and Haguro both wear a single armoured bracer in the manner of Japanese archers note  The hemlines of all "Student Council" jackets (save Hiei herself) are longer on the left side.
  • The Dragon: To Hiei.

Nachi

Sister ship of Myoukou, has top-notch sonar and communications gear and serves as the ears of Hiei's "Student Council".

  • Recursive Ammo: Nachi's signature attack is to launch one or more ICBM-sized missiles at the target, each of which is carrying between 12 and 16 torpedoes.
  • Red Oni, Blue Oni: The Blue to Ashigara's Red.
  • The Quiet One: Has a very muted personality compared with her sisters.
  • The Smart Guy: Is constantly asking Ashigara to slow down and study the data before charging into combat.

Haguro

Sister ship of Myoukou and member of Hiei's "Student Council". Initially an escort of Hiei and Myoukou, has since teamed up with Ashigara after they were both sunk by Iona.

  • Humiliation Conga: Forced to wear Hiei's "Student Council" uniform, was the first one sunk by Iona, reduced to only her (totally helpless) core and then swallowed by a shark. Now that she's been rescued she's still stuck playing second fiddle to Ashigara.
  • Token Mini-Moe: Is notably younger looking than the other members of Hiei's group, appearing only as a pre-teen instead of the more typical mid-late teens of the other members.

Ashigara

Sister ship of Myoukou and final member of Hiei's "Student Council". Initially paired with Nachi, has wound up with Haguro after they were both sunk by Iona.

  • Actually Pretty Funny: After getting beaned in the face with a torpedo, Ashigara floats stunned to the surface before cracking up with laughter.
  • Boisterous Bruiser: She really likes to get straight into combat. The moment Iona was detected she dove headlong into the water, knowing full well that it meant she could only use torpedoes (which she's not very good with).
  • Butt Monkey: Often self-inflicted, Ashigara's tendency for bull-rushing into a fight means that she doesn't get much respect and makes her defeats the most humiliating.
  • Red Oni, Blue Oni: The Red to Nachi's Blue.
  • Worthy Opponent: Wants to be this for Iona, believing in the Fair Fight. This is why she refuses to simply scuttle Iona from inside when she and Haguro end up in Iona's engine room.

Ise

Battleship of the Fleet of Fog, and Hyuuga's twin sister. Has taken over patrol duties from Kongou and Hiei since the hunt for Iona really took off.

  • The Ghost: No longer as of Chapter 63. She certainly looks like Hyuuga, but dresses like Maya in ruffles and bows. Has a sweet tooth as well.
  • Yandere: Potentially. The way she said she'd "give [Hyuuga] even more love," did not seem like Hyuuga would like it.

I-400

Voiced by: Aoi Yuuki

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

I-402

Voiced by: Aoi Yuuki

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.

  • Death by Adaptation: See I-400's entry.
  • Heel Face Door Slam: 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.

Nagato

Flagship of the First Oriental Fleet

Zuikaku

A Fog "assault ship" under Nagato, she joins I-402 in infiltrating Yokosuka, and in the process becomes Takao's virtual roommate in their hideout at the docks. Contrary to most Fleet of Fog Mental Models, Zuikaku shows none of the awkwardness in interacting with the local human population, and has become sort of a regular at the local market due to the seafood she catches.
  • Friend in the Black Market: Zuikaku herself is this to any restaurant owners looking for fish that can't be caught close to shore, like tuna. Just don't ask how she got them rod and reel, usually.
  • Kind Hearted Cat Lover: 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.
  • Non-Indicative Name: 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.

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.

    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
  • Cool Shades
  • Face-Heel Turn: Was a former war hero who captured the I-401. Now he's one of the Fleet of Fog commanders.
  • Schrödinger's Cast: While very much alive and even a major antagonist in the manga, Shouzou's fate is left ambiguous in the Ars Nova anime.
    • Only Mostly Dead: Previews for the second Ars Nova movie show that Shouzou is very much alive, and much like his manga counterpart, in command of Musashi.

Musashi

Superbattleship of the Fleet of Fog, and sister ship of Yamato.
  • Eyes Always Shut
  • Pretty in Mink: 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.

U-2501

Fleet of Fog submarine European Fleet.
  • Cry Cute: When Zordan orders her to cancel her mental model.
  • Does Not Like Shoes: Dances barefoot on her deck while she has the ability to do so.
  • Token Mini-Moe: Her mental model takes the form of an adorable child, a marked contrast to her crew who are all in their mid-late teens.

Zordan Stark

Captain of U-2501.
  • Combat Pragmatist
  • Germanic Efficiency: 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.
  • Evil Counterpart: Zordan Stark serves as one to Gunzou Chihaya. Both are human captains of crewed Fog submarines, match each other in tactical skill and share close personal connections with their crews. What sets them apart is Zordan's ruthlessness and their completely opposed views on Mental Models: Chihaya considers Mental Models as people and even leaves Iona in charge of his crew when he's not there; Zordan considers Mental Models a waste of resources on a crewed ship and forbids U-2501 from manifesting one, which is a shame because the one time she did U-2501 was adorable.
  • Smug Snake

    Unaligned Fog Fleet Ships 

Bismarck

The first Fog battleship sighted by humans. Last witness of the Admiralty Code, Flagship of the Fog's European Fleet.

Repulse

A fog battlecruiser that apparently defected due to a disagreement with the European Blockade fleet under the command of 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 her fellow ship Prince of Wales decided to force the issue, Repulse escaped into Pacific waters instead with her escort Vampire in tow.
  • Boobs of Steel: As a battlecruiser she has serious offensive firepower and is possibly the most well-endowed of any Mental Model seen so far, but somewhat subverts the trope in having weaker armor than a true battleship and an even weaker sense of confidence.
  • Prehensile Hair: A variation: it's not her actual hair, but Repulse has a pair of long ribbons on her hat which function the same way.
  • Meganekko
  • Meido: Not only has the uniform, but quite literally sweeps up damage with nanomaterial brooms.
  • Luminescent Blush: Easily flustered and embarrassed, especially whenever Vampire brings up the potential of working with humans.
  • Screw This, I'm Outta Here!: Had to abandon her patrol route after Prince of Wales decided she was disobeying orders.

Vampire

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 battlecruiser 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.
  • Servile Snarker: Vampire takes every opportunity to belittle Repulse's competency, but it's obvious that she's loyal to cruiser all the same.

Supporting Human Characters

     Japanese Government and Military Personnel 

Mitsumine

Current Prime Minister of the Central District of the three districts that the Fog's blockade has carved Japan into. He's proven far more adept at politics than his former naval career.

  • Number One: Was formerly Kita's XO when they took part in the Great Naval Battle.
  • Friendly Enemy: Views Kita as this; while they're bitter political opponents, he still has affection for his former captain.
  • Genius Cripple: By all accounts is a masterful political figure, despite being confined to a wheelchair with a life-support system since he was nearly killed in the Great Naval Battle against the Fog.
  • Good Is Not Soft: See the Chains of Commanding, below.
  • Machine Monotone: Possibly. He's yet to be voiced by an actor, but his speech bubbles are shaped like those used for radio communications, so his voice is certainly artificial.
  • Realpolitik
  • Reasonable Authority Figure
  • The Chains of Commanding: Is really feeling it after becoming Prime Minister. Has expressed a few times how he hates himself for having to make hard-hearted choices but holds out hope they're for the best.

Ryoukan Kita

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

  • The Captain: Was formerly a JMSDF destroyer skipper, and acquainted with Gunzou's father.
  • Friendly Enemy: 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.
  • Honor Before Reason: Inverted, Kita gives a couple of his old Army colleges a severe dressing-down over the Osakabe fiasco, which had been motivated by the Army's overwhelming desire to do something after being sat idle since before the Great Naval Battle. After the Iwo Jima disaster, Kita resigns from office in order to minimize the fallout from the affair rather than weaken the army's position further.
  • No, Mr. Bond, I Expect You to Dine: Gunzou and his crew are treated to this in episode 3/Chapter 8. During dinner (of which only Iori actually eats anything) Kita tries to convince Gunzou to return Iona to the Japanese government so they can put a "proper crew" on board. The arrival of Haruna and Kirishima adds some urgency to the discussion, but not the (strained) civility).
  • Realpolitik: Prime Minister Mitsumine and Asst. Secretary Kamikage are his primary opponents in the power struggle within the Japanese government until Kita resigns to save face for the Army.

Kamikage Ryujirou

Assistant Secretary to Military Command of Ministry of Defense (later promoted to full Secretary), Kamikage is the government official most sympathetic to Blue Steel. It was his idea to use I-401 to transport the Vibration Warhead data to the USA in the first place, which forms the major plot of the franchise.

  • Good Is Not Nice: Is entirely willing to play hardball with political opponents or Japanese citizens if he believes it is in the best interests of the nation. He is ''considerably'' more ruthless in the anime.
  • Realpolitik: The power struggle between the various parties and regional capitals in the Japanese government is very real. Kamikage, despite his relatively young age, is a consummate player.
  • Reasonable Authority Figure: Is the highest ranking official in the Japanese government to view Gunzou and Blue Steel as assets and not liabilities. Is starting to win the Prime Minister over to his way of thinking.
  • The Chessmaster: Has a lot of assets to move around the board, these only grow after his promotion. All for Japan.
  • The Strategist: As part of his job in the Ministry of Defense.

Cruz Herder

One of the United States Marines stationed in Japan before the fog blockade now part of the Japanese Navy as a special forces detachment.
  • Badass Normal: He's yet to engage in combat but interactions with other characters detail his professional reputation as one.
  • Deadpan Snarker: His casual and often irreverent mannerisms contrast sharply with the much more uptight Kamikage, his primary contact and ally in the Ministry of Defense.
  • Older Than He Looks: Given his training and the amount of time confined to Japan, Cruz is probably in his forties. Not that you'd know by looking at him.

Daisaku Komaki

Captain of the Hakugei 3, Japan's latest and greatest submarine.
  • Adorkable: Badass ship captain, yes. Completely useless when it comes to women, oh yes. His bumbling attraction to Mauri makes him one of the most endearing of the human characters.
  • Badass Normal: Becomes captain of the first man-made ship to sink a Fog warship. That it was Haruna and Kirishima at the same time just makes the victory all the sweeter. Willing to intervene in the escape of Repulse and Vampire into the Pacific.
  • Hotblooded Sideburns: An understated, well-trimmed example, but they do go all the way to his jawline.

Maruri Hibiki

Voiced by: Kana Hanazawa

Former Sonar operator of I-401. Transfers to the Hakugei because of her experience in Blue Steel.

  • All Love Is Unrequited: Is still holding a candle for Gunzou. His inability to notice her affection and the massive guilt he carries from losing Kotono is a big part of why she left Blue Steel and rejoined the Navy.
  • Love Cannot Overcome: Even though she was the first crew member to join the Blue Steel because she was in love with Gunzou, she couldn't handle the risks of being in Blue Steel.

Makoto "Osakabe"

Prime Minister of the Northern District and a Design Child.
  • Creepy Child
  • Dude Looks Like a Lady
  • Team Switzerland: Is willing to support either the Japanese government or the Fleet of Fog as long as Hokkaido benefits from the alliance.
  • The Leader: Was genetically engineered to be a capable leader without humans flaws like corruption or greed.
  • The Stoic: Neither is he capable of strong emotions, being engineered to be objective and dispassionate. His concern for Makie and by extension Haruna, Kirishima and Maya is noted by himself as deeply uncharacteristic.

    Other 

Makie Osakabe

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

Lawrence Valentine/Toujuurou Osakabe

Makie's overprotective butler. Unknown to Makie, Lawrence is actually Toujuurou Osakabe, her "grandfather" and creator.

In Ars Nova, he is Makie's adopted father and a prominent weapons researcher. 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.

  • The Atoner
  • Battle Butler: Although Makie just knows him as Lawrence, secretly he is...
    • The Professor: Involved in the creation of Makie and the other Design Children and her unseen 'grandfather'.
  • Disease Bleach: His hair turned white as he watched most of the design children die in front of him.
  • Faking the Dead: 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 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.
  • Heroic Sacrifice: Stopped the Army from assassinating Makie, but it... uh... yeah.
  • Omnidisciplinary Scientist: 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, ostensibly for her own protection.

  • Death by Adaptation: Hinted to have committed suicide in the Ars Nova anime.
  • Gilded Cage: She's under house arrest in a mansion that's heavily monitored by security cameras. The place is lovely with a huge greenhouse/aviary in the back where she can still do her research on birds and has a domestic staff to handle all the chores, but she's still banned from leaving the property.
  • Shipper on Deck: 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.

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.

  • The Ace: Her reputation among Gunzo's schoolmates. Sou even calls her "the wall that Gunzou could not overcome".
  • Childhood Friend: To Gunzou and Sou.
  • Cynicism Catalyst: Her death was the prime motivator for Gunzo to change the status quo of the world, and ally with Iona.
  • Posthumous Character: Died in an accident two years prior to the start of the story, however...