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Physical Appearance
Age ???
Monster Species Black Slime
Gender Unknown, if she even has any; self-identifies as female
Height Dependent On Water
Weight Dependent On Water
B-W-H Dependent On Water
Monster Profile
Occupation None
Relatives Hot Spring Slimes (creations/"childrens")
Media Debut
Manga Chapter 51

Nega-Suu is a giant Black Slime that stowed away aboard a cargo container ship to Japan. Upon discovery, the President of the Black Lily Advanced Materials Laboratory attempted to transport her to his facilities without the government's notice but a chance encounter with Suu saw Nega-Suu escape her transport truck and enter the water canals around Tokyo. An aggressive and stronger slime, Nega-Suu found Suu's unique experiences desirable and intended to draw Suu to her and absorb the smaller slime's body into her own; eating the smaller Slime's core to gain her experiences and abilities. She makes her debut at the end of Chapter 51 before appearing as the main antagonist of Volume 13.


As a Black Slime, Nega-Suu's body can take different forms depending on how much water she has ingested. She is black in color due to the impurities in her body.

In her blob form, Nega-Suu resembles a giant octopus-like mass, with the ends of her tentacles having pointed appendages. Similar to Suu, she has a long Slime tentacle on top of her head. As Mr President explains in Chapter 54, Nega-Suu's body has taken on a gel-like consistency from her constant water intake, making her no longer soluble in water.

After Nega-Suu accidentally absorbed a small part of Suu's body in Chapter 52 and the polymer that the Black Lilies staff used against her drained too much water from her, Nega Suu's body took on a more solid, humanoid form. In this form, Nega-Suu mostly resembles Super Suu, but with a more aggressive appearance. She has sharp fingernails on her hands, and spike-like appendages on her shoulders, on the ends of her tentacles, on her elbows, and on her knees.


Not much is known about Nega-Suu's personality, or if she is even fully sentient. What is known is that she is a highly aggressive predatory Slime, who is extremely determined to absorb Suu to add to her own capabilities. Due to this aggressive and determined nature, Nega-Suu does not seem to care about the repercussions of the damage she does, even if that includes the deaths of others. Thus Nega-Suu can easily be regarded as one of the most dangerous Liminals that Kimihito and his homestay girls have encountered so far.

While it's not entirely clear whether Nega-Suu is fully sentient, she was at least able to act out a plan as shown in Chapter 52 when she communicated telephatically with Suu to lure the intelligent Slime girl to her. She also addressed Suu by her name, which implies that Nega-Suu has at least a basic understanding of self-awareness.

Despite her malevolence, Nega-Suu also seemed to develop a softer side of her personality later on, because in Chapter 66 it can see how she read a book in the captivity of the Black Lily Laboratory, which shows an open interest in this activity. It can be assumed that the main reason for this activity is to allow Nega-Suu to gain experience on its own, which makes it unnecessary to absorb an intelligence Slime. Later, Nega-Suu created dozens of new humanoids Slimes, although the reasons for this creative, perhaps even maternal act are completely unknown.

Since Black Slimes are created when the home of normal Slimes are polluted with toxic waste, it can be assumed that Nega-Suu originally had another personality, as Suu is also known that certain substances such as poisonous plants can change your personality for a short time.

Skills and Traits[]

Physical Traits[]

Nega-Suu Render
  • Liquid Body: As her physical makeup is a liquid substance, her body acts in the same way. She can place people and objects inside of her body, or have them pass through. This makes her difficult to catch, as she can simply pass through the restraint, such as with Rachne's webs.
    • Invulnerability: Her physical makeup also makes her seemingly immune to any form of physical damage. Even when she solidifies herself, she is still immune to any form of blunt impact.
    • Adhesive body: Nega-Suu also has the ability to stick to any surface, such as ceilings.
    • Acidic body: The acidic properties of Nega-Suu's body are far stronger than those of regular Slimes. This is due to her evolving to break down nutrients in even the most inhospitable of environments.[1]
    • Water absorption: Nega-Suu is capable of absorbing water into her body. For some reason, she is able to absorb far more water than any regular Slime as she can grow to giant sizes purely by absorbing water. She can also expel her internal water in highly pressurized streams from her mouth.[2][3]
    • Assimilation: Nega-Suu is able to absorb other Slimes into her body, fully assimilating the other Slime's knowledge, memories, and experiences, and fully removing any trace of that Slime's individuality. Assimilating a small part of Suu's being allowed Nega-Suu to take on a humanoid form similar to her.[2][3]
    • Dilution immunity: As opposed to other slimes, Nega-Suu is somehow able to prevent herself from dissolving when exposed to large bodies of water, such as lakes or rivers.[2][3] This is due to the large amount of contaminants she has absorbed.[1]
    • Skeletal Structure: Highly unusual for a Slime, Nega-Suu has formed her own endoskeleton to support her body. This skeleton is made out of the impurities stored in her body for a long time.[1]
    • Duplication: As shown in Chapter 66, Nega-Suu can reproduce by absorbing filtered onsen water containing the DNA of Liminals that have bathed in the water. In doing so, she created the Hot Spring Slimes, who also have individual characteristics of other Liminals, such as Nekomimi ears, due to the Liminal-DNA with which they were created.
    • Weaknesses: Despite lacking a Slime's biggest weakness, Nega-Suu can still be defeated. For one, the proper chemical substances can rid her of most of her internal water. Likewise, like all Slimes, Black Suu is completely powerless should her core be removed from her body and isolated from any liquids.[2][3]


Not much is known about Nega-Suu's past, but according to the Slime info card, a Black Slime evolves from a normal Slime when its home is polluted with toxic waste. It is possible that this event led to Nega-Suu's aggressive nature in the first place, although this is unconfirmed. According to Nega-Suu's secrets, up until the events of Volume 13, she didn't have much to do with humans, which made her not much educated or experienced.


The Black Lily employees discover Nega-Suu on the ship.

At some point, Nega-Suu stowed away on a freighter owned by Black Lily Advanced Materials Laboratory, in an attempt to enter Japan for reasons unknown. The crew of the ship found her in one of the containers, and managed to capture her inside a tanker for transport. Although no one could explain how Nega-Suu got on the ship in the first place, Mr President saw this as a good opportunity to study the Black Slime, so he hurriedly obtained import papers for her. However, since the normal procedure for this would have cost too much time and money, Mr President filed for an exception under "new materials for EXPO use".

Mr President later suspected that the reason why Nega-Suu wanted to come to Japan was to absorbed Suu to gain all of her experience. However, if Mr President's assumption is correct, it remains unclear how Nega-Suu outside of Japan could have even found out about Suu's existence. [2]


Liberation by Suu[]

After the Black Lily Laboratory brought Nega-Suu to Tokyo, they loaded the Black Slime into a tank truck and parked the vehicle in the parking lot of the Tokyo International Exhibition Center on the second (and final) night of the EXPO in Chapter 52. The location was specifically chosen as a camouflage so that the laboratory employees could later use the tanker truck to smuggle themselves under the departing cars at the end of the EXPO, so that they could secretly bring the Black Slime during the night to the laboratory.


Nega-Suu locks at Suu from the tanker truck.

By chance, however, Suu was in the parking lot at the time after she was separated from Miia, Centorea and Mero and getting lost when the other homestay girls where tracking Curie. When Nega-Suu became aware of Suu's presence, she communicated silently with the other Slime girls, whereupon Suu climbed onto the container of the tanker and opened the lid of the tank to free Nega-Suu, apparently unaware of the danger the Black Slime posed for her.


Suu opens the tanker truck.

However, in the moment Suu opened the lid, the tanker suddenly drove off, whereupon Suu accidentally got her right hand into Nega-Suu's Slime body and then fell off the tanker truck as the vehicle drove off. Suu waves after Nega-Suu as the Black Slime slowly freed herself from the tanker, before Suu noticed in the next moment that her right hand was suddenly missing because it had been absorbing through the contact with Nega-Suu's body insides. But she was able to immediatelly regenerate her missing hand. Shortly afterwards, Suu was found bei the girls of the MON who brought her back to the Kurusu house.

Because of the Tunker Truck's departure, Nega-Suu had no opportunity to attack Suu at this time, whereby Suu also had no idea that the Black Slime had the intention to do so. Suu, perhaps because of her childlike naivety, didn't connect the lack of her hand with a possible danger that Nega-Suu could pose to her. By absorbing Suu's hand with the information gathered from it, Nega-Suu eventually gained the ability to change her slime body structure into a humanoid form, although she was unable to use this ability due to the amount of excess water that was still in her body.

Rumours about the "Nessie Monster" and telephatic contact with Suu[]


The police officer saw the "Nessie monster".

Several days later after Nega-Suu's escape, rumours spread in Tokyo that some sort of "nessie monster" had been spotted in the river that flows right through the city. These inaccurate rumours were due to the fact that no one had seen Nega-Suu in full, only the feeler she has on her head in her blob form, which from a distance looked like the neck and head of a Plesiosaur/Nessie-like being. Kimihito and his homestay girls also learned about the rumours, whereby Miia was skeptical about them, although Kimihito pointed out that there were several eyewitness reports. One of these eyewitness was the bicycle police officer who, during his morning patrol in the fog, vaguely saw Nega-Suu and suffered a terrible shock.

Satellite Suu

Suu behaves very strangely as she tries to receive Nega-Suu's message.

Finally, Nega-Suu tried to contact Suu telephatically at the Kurusu house, which didn't go unnoticed by Kimihito and Lala because Suu suddenly behaved very strangely. Nega-Suu told Suu that she wanted to meet her, to which Suu accepted immediatelly and without hesitation, obviously unaware in her childlike innocence that Nega-Suu only wanted to lure Suu to her in order to absorb her and her experiences, in other words, the intention to kill her. As Suu ran out of the house, Kimihito and Lala, who didn't know what was going on but were worried about Suu's strange behaviour, tried to stop her but failed.

After a wild chase across Tokyo, Kimihito and Lala finally found Suu near a body of water, not knowing that Nega-Suu was lurking in the body of water and was getting ready to emerge. In the meantime, however, the employees of the Black Lily Laboratory had also started looking for Nega-Suu, where they were able to track down the Black Slime by using a transmitter that they had implanted in her Slime body. However, when the staff arrived on side, they mistook Suu for the Slime they were supposed to catch, vaccumed her up and took her away to the Laboratory, much to the shook of Kimihito and Lala. After Suu's disappearance, Nega-Suu disappeared back under the surface of the water before anyone could notice the presence of the Black Slime.

Zoological Classification[]

Main article: Slime
MonMusu Black Slime

Black Slimes (スライム, Burakku Suraimu) are slimes that have turned black because their homes are polluted by toxic waste. It is impossible to determine their original color. Though they often make dark and satirical comments on society, they are not careful with their word choices and don't generally understand what they are saying. They are extremely violent and hostile to humans.


  • Nega-Suu, along with Wladislaus Drakulya, is one of the few antagonists who have proven to be a real threat to the point where their actions are taken entirely serious and they have no humorous moments. In the case of Nega-Suu, this is partially mitigated by the fact that her attemps to absorb Suu were not out of malice, as her rather lack of sentient made her more like an animal, who simply follows the nature of a wild Slime to produce new Slimes. Nevertheless, she is still one of the most dangerous Liminals Kimihito and his homestay girls had to face.
  • In Chapter 54, Mr President states that his company has implanted a transmitter on Nega-Suu so that she can be located at any time. However, it is unclear how it should even possible to implant a transmitter into a Slime, since a Slime is liquid, which is why a transmitter cannot be attached anywhere. In addition, there is the fact that Nega-Suu is a Black Slime, so a transmitter would be decomposed by the acidity of Nega-Suu's body.
  • Mr President suspected in Chapter 54, that Nega-Suu only wanted to come to Japan to absorb Suu. However, this assumption also raised the question of where Nega-Suu found out about Suu's existence at all.
  • Unlike Suu, Nega-Suu has no pupils, even in her humanoid form. This is probably a deliberate stylistic device by Okayado to show Nega-Suu's violent and possibly not fully sentient nature.
  • In Chapter 81, a Slime girl appears who bears a strong physical appearance to Nega-Suu, which is further supported by the fact that the Black Lily Laboratory uses the Slime girl to filter the water in the Black Lily Waterpark, similar to how they also used Nega-Suu in Chapter 66 to filter the onsen water in the Arctic Inn. However, in Chapter 81 it is not confirmed beyond doubt whether the filtration Slime girl is really Nega-Suu, as neither Kimihito nor someone else identify the girl as Nega-Suu.
    • Since the filtration Slime girl is also a "daughter" of Suu's mother, this would mean that Nega-Suu, if she is really the filtration Slime girl, almost killed her own sister by attempting to absorb Suu in Volume 13.
  • Nega-Suu's exact whereabouts are currently unknown, but judging from the events of Volume 16, she is likely still in captivity at the Black Lily Laboratory.


  1. 1.0 1.1 1.2 Volume 13 Omakes
  2. 2.0 2.1 2.2 2.3 2.4 Chapter 54
  3. 3.0 3.1 3.2 3.3 Chapter 55

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