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Physical Appearance
Monster Species Fishfolk
Gender Male Male
Monster Profile
Occupation Secondary butler of Neptune royal family
Media Debut
Manga Chapter 34

Sebasstian (サバスチャン, Sabasuchan) is the secondary butler of Neptune royal family. He makes his debut together with Flounnder in Chapter 34.


As a Fishman, Sebasstian resembles an anthropomorphic fish in appearance, with his arms and legs placed where his flippers would normally be. Unlike Flounder, he is slim and tall, and he is lighter-skinned, with his lower jaw, front neck, and hands almost white. He also has webbed fingers.

Sebasstian wears a black tuxedo with a black bow tie and black pants. He also has a small monocle on his left eye.


Sebasstian takes his duties as a butler very seriously and is generally polite but also a bit strict. He takes great pride in his job and is quick to get upset when things don't go as planned, although he also shows gratitude to those who help him.

Although Sebasstian is polite, like Flounnder, he can be very selfish, as he always puts his personal disadvantages first when faced with a problem, even when others' lives are in danger. This is clearly seen when he was immediately concerned about his job, after Mero's "kidnapping" by Octo, to which Kimihito angrily reminded him that this was secondary given the potential danger Mero was in.

While Sebasstian take his job very seriously, he also seems to have a deceptive side, as he confesses in Chapter 36 that he and Flounnder were secretly trying to sneak up on Octo, hoping she could use magic to turn them into handsome Fishmen. Because of this, the two butlers also refused to help save Mero, as they didn't want to take responsibility for their secret visit to Octo.

The two butlers also only warned Kimihito and the girls about the danger of the giant sea anemones after they entered Octo's cave. It is to be viewed with scepticism whether the two butlers really forgot this detail or whether they deliberately kept it secret, as they feared that they would otherwise have to take responsibility for Mero's rescue themselves, if Kimihito and the girls had refused. In any case, it shows that Sebasstian is sometimes very careless.

Skills & Traits[]

Personal Skills[]

  • Driving: As seen in Chapter 35, Sebasstian can drive a car and presumably has a driver's license as well.

Physical Traits[]

  • Fishman Physiology:
    • Amphibious: As a Fishman, Sebasstian has gills on the cheeks of his fish-like head, which allow him to breathe water. He also has a humanoid respiratory system that allows vocalization and mouth breathing. As long as his gills remain moist, he can breathe on land.
    • Swimming: As a Fishman, Sebasstian is an excellent swimmer by nature. Since he has gills, swimming actually plays a role in his natural breathing, which allows him to breathe underwater indefinitely without having to surface.


Zoological Classification[]


Fishfolk are a pseudohuman race resembling, in effect, humanoid fish with arms and legs, and with webbing between their fingers. Fishfolk are capable of breathing air and, ironically enough, are more capable on land than the far more humanoid Mermaids thanks to their functioning legs.

While appearances vary between individuals, the majority of their body resembles a fish, complete with visible gill covers, a thick tail, scales, and occasional tendrils above the mouth. The head appears to be at least a little different from a common fish's, however: the mouth is more articulated and capable of forming words, and the eyes, though lacking lids, have a noticeable degree of expression to them.

The Fishfolk seem to be in direct service to the Mermaid crown, and evidently handle most terrestrial affairs for their lieges.


  • Sabasstian's name derives from the butler Sebastian from the popular anime adaptation of Johanna Spyri's Heidi. Ever since, in Japanese popular culture "Sebastian" has become a stereotypical butler name, similarly to "Jeeves" in English culture.
    • His name is also a pun on "mackerel" ( Saba?).
  • In the official translation his name is spelt "Sebasstian"
  • Besides that, in the manga and anime by Yana Toboso is a butler called Sebastian. in one of the files where they discuss Octo, you can see their visions of how they would look as handsome butler mermen, as they put it. One of the visions has a striking resemblence to Sebastian by Yana Toboso. I feel as if that might be a reference. The other butler as shown in the image looks a lot like a butler names Claude, also from Black butler.
  • Sebasstian, along with Flounnder and Wladislaus, is one of the few named male Liminal characters in the manga series.

Main Characters Kimihito KurusuMiiaCentorea ShianusPapiMeroune LoreleiSuuRachnera ArachneraLala
Secondary Characters Bicycle Police OfficerCathylDoppelDracoKiiKuroko SmithLilithManakoMerinoMr PresidentPoltTionishiaYukioZombina
Minor Characters AbulAideAlbaAlucaAlusia Van DalsiaAnkaraArachne LeaderArbatelAyaBahkurinBoerCacasiaCamembertCaraCashmereCathyl's BoyfriendCentorea's MotherCharolaiChedaCheron Du PellChevioChizuCorriedalCottCottaCreamCurie DrakulyaDrysEmmaEmmentaFiiFlounnderFreesiaGaruGillGodaHakuto (manga)Ils NinetaJamunaKarakKasegiKillaKinoKinuKiruraruKyuukiLeechiLizLuthrosMaikaMaruMeamil AiraguMeroune's MotherMiia's MotherMilMimi (manga)MoskiiNega-SuuNicole UnicoleNubiOctoOrc LeaderPapi's MotherParminoPegasania BellerophonPolice ChiefPonePurse ThiefQuarkRacletteReggianoRem NighdremRen KunanzukiRicottaRomRuyèrSaaneSankaSapphoSebasstianSekmetiShequaShibaShii-MiiShiishiiStudmuffinSuu's MotherTexlThe Racist CoupleTiltoToggenTokaraTonUrtVikkWani OtokoWladislaus DrakulyaYatsumeYuuhi HajimeZarellaZola
Game-exclusive characters AbyssActiaAiAluruAnuraArayaArielAsiaBelleBimaBisqueČeskáChioneChocolaCholanDeathDinaEldaEmEmethEnaErisFalFan LongFereFiFlareFranFrozeGalaGinaHakutoHalifaHaruHoneyHoroHydraIormuJelliJerezKagachiKaloloKasukaKehpKerosKomachiKuraKuruwaKuuKuuneKyouKyureLatoLeaLetheLizaLucineLycaMaiMashuMediaMemekoMimiMirajMisakiMitiMoiraMokunaii the 11thMyuuNanaNancyNan QueNemesNiaPeacePiratiPaulaQueenQuessQukulRanReiRemReshiaRiadoRoheRostyRuberuRudoruRudiRuiRukaRusSakiSalaSasamiSeaSeinShaiaSharonShianaShenayShinotchaShireSitriShizukaSophiaSuzieSya HuTatakeTeriosTierraTitoTolepasTsenUnyiVynetteWereYoukoYuki
Other Characters DubtwoJohn SmithOkayadoPako-chanPoltfanSalmonThe Eight BrothersThe Interspecies Reviewer
Groups ANM48Blood SuckersCommunal HusbandsCultural Exchange Security SquadEchidna TribeHot Spring SlimesJapan National Police AgencyKimihito's Homestay GirlsMedusa TribeMelusine TribeMiia's FriendsMiia's TribeMob CharactersMonster Ops: NeutralizationNeighborhood KidsOrc Culture Recultivation LeagueRachnera's TribeResidents of Black Lily RanchSno Ball Hot Spring Resort AttendantsStudents of Grimoire High SchoolTALIOThe Centaur Girls
Animals/Pets Asian Giant HornetBatCatfishCrabDoku-chanDolphinMegumiPapi's ChickiesPiranhaSea AnemoneStingrayWild Boar