Manga / Cells at Work! CODE BLACK

aka: Cells At Work Black

If your local PSA won't get you to quit smoking, this manga will.

We have to wipe out all foreign substances from this body to protect it! Work, work, work until you drop!

—Helper T-Cell Commander

Cells at Work! is a relatively-lighthearted Anthropomorphized Anatomy story based on a hypothetical human body in generally good health, so most of the health issues described there are acute and are from external sources. But sometimes, the problems stem from the body itself - how about diseases due to poor life choices? How do your cells handle overexertion or hormone imbalance? What happens when the pathogens are on the winning side for once, what triggers organ failure?

That would be a bit too dark for a Shonen series, and too jarring for such a bright and cheerful world, so they set a spinoff to that effect in an older man's body instead.

Welcome to the daunting world of Cells at Work! CODE BLACK^note Originally released as Hataraku Saibou BLACK, or Cells at Work! [BLACK], where an unhealthy body is depicted as a Dangerous Workplace gone worse. In this landscape ravaged by bad habits, the cells inside have to deal with the effects of lethargy, unsafe sex, stress, smoking, and more — often in the bloodiest ways possible, whether they want to or not. Shigemitsu Harada and Issei Hatsuyoshi are in charge of the plot and art, respectively, making this the first installment done without Akane Shimizu's direct involvement. It ran in the Seinen anthology Morning from 2018 to 2021.

Kodansha Comics obtained the North American license for the manga.

Other Spin-Offs of Cells at Work! include Cells at Work and Friends!, Cells NOT at Work!, Cells at Work: Bacteria!, Cells at Work: Platelets!, Cells at Work: Baby!, Cells at Work! Lady and Cells At Work! White Brigade.

An anime adaptation was produced by Liden Films, which started airing on January 7, 2021, alongside the second season of the original Cells at Work!.

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Cells at Work! CODE BLACK contains examples of the following tropes:

• 2D Visuals, 3D Effects: Like the main series, background cells are rendered in 3D for the anime.
• Acceptable Breaks from Reality: The author acknowledges that in the second part of the series, the original host body would be unable to donate blood as he had suffered a heart attack. ^note To be exact, the host was stented, which means he would need to take blood thinners in the long term. This precludes the possibility of blood donations. However, it continues the story and allows him to explore other, more serious diseases and conditions, so it's excusable.
• Action Girl: The Neutrophils and Macrophages, both being types of immune cells anthropomorphized as human females while tasked with exterminating foreign entities.
• Adaptational Badass: Every single example of bacteria showing up here that were also in the main manga get a massive upgrade in both appearance and threat, with all of them looking scarier and more badass along with actually having the potential to seriously damage the body, which makes a lot of sense because the weakened immune system from a bad life-style both makes the invading pathogens stronger by comparison and allows deadlier strains to develop.
• Adaptational Dumbass: While the majority don't have much smarts anyway, the bacteria in the main manga all at least have a working intelligence, able to converse with and gloat towards the body cells. Here, while there are still a few bacterium that can talk and have discussions, the vast majority have been reduced to mindless berserkers who care only about killing and infecting the cells.
• Adaptational Expansion:
  • Following the R-Rated Opening and title, the first anime episode includes a scene of AA-2153 and his fellow newbie Red Blood Cells watching a video presentation about the human body, which shows off the massive differences in the character cast compared to the main series long before said characters get officially introduced. The video is presented in a reception not unlike the mass onboarding events in Japanese employers, fitting the "body=employer" theme.
  • A number of scenes are added and several existing moments re-configured to emphasize the relationship between the series' leads; for instance, U-1996 accompanies AA-2153 to the nursery where the spermatogonia grow, and after the Gonococcus are defeated he encounters her working out and recuperating from her injuries.
  • The Gonococcus attack is used to justify the Killer T Cells going berserk, adding several scenes of them covering for the decimated White Blood Cells to show their increasing strain before they finally snap against the Hair Follicle Cells; in the manga, their hair-destroying rampage was their debut scene.
• Ahem: The blurb for the English edition sees a case of its euphemistical use:
  [...] Ulcers, fatty liver, trouble (ahem) downstairs… It’s hard for a cell to keep working when every day is a CODE BLACK!
• Amazon Brigade: The Neutrophils in this manga are all women, which creates a further contrast to the ever-manly Killer T Cells. The Macrophages are also all-female like in the main story.
• Anthropomorphized Anatomy: Just like the source material, a depiction of cells and their functions as humans. This series, however, has a much less "happy and healthy" depiction of them.
• Anyone Can Die: The only cell characters absolutely guaranteed to survive the story (and even that is somewhat iffy about it staying true forever) are AA-2153 and U-1196. Everybody else is fair game for sudden and unexpected deaths. It doesn't matter how long it might take, from dying in their introductory chapter to practically being a main character for half the series before biting it, cells dying always looms over the story. As can be seen by AA-2153's best friend AC-1677, who despite being as much a main character as the two protagonists, still ends up dying before the story even reaches the end of the first half (or in the Anime's case, the end of the season).
• Arc Words:
  • "Deliver the oxygen," which is both AA 2153's primary job, alongside what he WILL do, against all odds, disasters, and self-inflicted diseases and conditions the host body brings upon itself.
  • "Because that's my/our job," which is at first used as words of encouragement to rouse people like AA 2153 to keep going, but later takes on grimmer tones, of the various Cells resigning themselves to the endless and seemingly futile task of trying to maintain a body that has no interest in maintaining itself.
• The Artifact: The fact that AA2153 and U-1196 get transferred to a different host is the artifact of the series getting an unexpected green light to continue beyond the heart attack arc. In the beginning it was intended for the Cells to die with the first host.
• Artistic License – Biology: Unlike the main series, which at least tries to depict bacteria as somewhat resembling their real-life morphology, the Gonococcus (Neisseria gonnorrhea) is straight-up depicted as a gruesomely detailed five-headed penis monster.
• Ascended Extra:
  • The Brain Command center as a whole has a massively increased role in the story compared to the main series. In the original Cells at Work, the Brain cells only rarely factored into the story, with their biggest role being in the hypovolemic shock incident, and even then only sparsely appearing. In this story they get a massively increased role, to the point that a Brain Cell Commander and his subordinate Brain Cell are prominent characters. This is especially so in the anime, as the already-increased prominence is expanded even further, with them going from more notable Recurring Extras to outright main characters. The overall expanded role is pretty well displayed through their presence in the anime credits, as not a single Brain Cell is visible in the Cells at Work! openings of either season, whereas not only does the Code Black opening show them twice like the other major characters, they even get a scene during the ending credits.
  • The Platelets experience a zigzagged example of this. In the manga they got a case of Demoted to Extra compared to the main Cells at Work!, as while they quite obviously are still present, as a whole they've been lessened to background characters, not even having a representative Leader. The anime, on the other hand, reverses their demotion as another way of Adaptation Expansion, having several added scenes in each episode showing them repairing the incredibly frequent damage the body goes through, with it even creating a Canon Foreigner in the form of its own Japanese Delinquent version of Leader-chan.
• Ascended Fridge Horror:
  • Since Cells at Work! portrays the anthropomorphized cells of the body as attractive young people, it does come up with a horrifying issue: what would autoimmunity look like in such a setting? This was finally revealed in here, where the Killer T cells, driven insane by the harsh conditions and the constant stimulation of cytokines, have gone berserk and started murdering innocent body cells, mistaking them for cancer cells in their crazed rampage.
  • Cells are actually recycled by being eaten by certain immune cells. We get to see this at the end of chapter 2, where it's appropriately depicted as a dirty secret.
• Asshole Victim: The anime adaptation has two "senpai" Red Blood Cells that are constantly insulting, belittling, and being overall condescending to AA-2153 and AC-1677, frequently attempting to act as a Toxic Friend Influence, such as being the ones that coerce AC-1677 into getting addicted to caffeine. This all comes to a head in Episode 8, where the senpais try to kill the duo by knocking them into a blood clot, purely based on AA-2153 standing up to them. That same episode has them experiencing a Karmic Death by getting crushed and absorbed by the aforementioned blood clot when it comes rolling out to block the lungs. While the life-threatening trouble of the pulmonary embolism caused by the blood clot is a massive concern, there are no tears shed or care given when these assholes end up as collateral damage.
• Audience Shift: CODE BLACK is a seinen spinoff of Cells at Work!, although the similarity ends at the usage of Anthropomorphized Anatomy and basic character designs. The content shifts from body functions to diseases in CODE BLACK, and is Darker and Edgier, Hotter and Sexier, and Bloodier and Gorier than the original, to the point that its creators are ecchi artists. It got a surprisingly good enough reception to get Un-Cancelled, and Kodansha Comics considers it appropriate to license it in the US, despite having a 18+ rating.
• Bait-and-Switch Credits: The opening of the anime is incredibly cheery and uplifting, making the series seem just as wholesome and comedic as the main series... despite first showing at the end of Episode 1, where everything shown makes it quite obvious that it's definitely going to be nowhere near as "wholesome and comedic", even if there are going to be occasional moments of levity amidst the darkness. Though the very end of it has its own Bait-and-Switch, having Red Blood Cell falling into a pit of darkness before waking up, implying the majority of the OP was RBC's hopeful dreams about what working in the body would be like, only to be dragged back into his horrible reality.
• The Big Guy: The T Cells of this body are absolutely ripped.
• Big Red Button: The Helper T cell has one that powers up Killer T cells with cytokenes. In his overwork-caused madness, he pounds it.
• Bittersweet Ending : After going through hell and back over many tragedies and deaths of fellow cells throughout the series the main characters AA2153 and U-1196 overcome their despair and live life to the fullest. Conditions have finally improved by then, somewhat, but the body is still scarred and damaged and the cancer could always return. They are both aware that death is inevitable, but it won't come today.
• Black Comedy:
  • As tragic and sad as it may be, there is something inherently funny about the idea of pus discharge of gonorrhea being depicted as a Viking Funeral.
  • Also the image of sperm cells as happy children and the fact that Red Blood Cell dramatizes about their tragic fate.
  • The seriousness and despair with which the Red Blood Cells and the Brain command center treat their host suffering from erectile dysfunction. (On the other hand, given the Existential Horror below, well...)
• Bloodier and Gorier:
  • Unlike the main series, antigens aren't the only characters that experience horrific deaths. Here, AA-2153's fellow Red Blood Cells are brutally mutilated daily, and no matter how much of a fight they put up, U-1196's sister White Blood Cells often end up biting it in equally gruesome ways against the various bacterium and virii they face.
  • In addition to the bloody deaths applying to the body's cells here, the deaths themselves, and even just the general injuries, are overall more bloody, gory, and outright disturbing. For example, unlike how Neutrophils in the main manga kill by just slashing at the antigens, who drop to the floor whole with "x"'s in their eyes, the Neutrophils here get creative with their kills, including impaling the skulls, dismemberment, or outright bifurcation, all of which are even bloodier than the original antigen deaths already were.
• Blood Is the New Black: Neutrophils are almost never seen without massive red cytoplasm stains, U-1196 especially.
• Book Ends:
  • The anime begins and ends with AA-2153's monologue on the duties of the red blood cell.
  • The opening theme ends with AA-2153 waking up suddenly to his alarm, and the ending theme with him going to sleep.
• Body Horror: Plenty of examples, like the Red Blood Cells effectively asphyxiating from carbon monoxide exposure in the first chapter.
• Body of Bodies: A blood clot in the leg is depicted as a mass grave, and when the human gets up from a weekend-long TV marathon, it becomes a pulmonary embolism depicted as a wad of fused corpses steamrollering everything in its way.
• Break the Cutie: AA-2153, with his breakdown after his friend AC-1677 sacrifices his life to save him, and the poor Hepatocytes at the Liver when the body starts to drink excessively, daily.
• Cast of Snowflakes: Strongly contrasting how only Red Blood Cells had major variety to their designs in Cells at Work! while every other cell type was a Clone Army with minute visual differences, with all Ordinary Cells being completely identical, this story has every single cell possess decently varied looks beyond hairstyles, which is especially notable for the Ordinary cells, since not only do they go from a male One-Gender Race to 50/50 male/female, each of them are quite varied within those genders, ranging from close to the original Generic Guy design to visibly middle-aged folk.
• Central Theme: What can happen when you don't take care of your body and why you need to take care of it.
• Code Emergency: The English title refers to a hospital color code that, in one major Los Angeles hospital, means the hospital is over capacity.
• Cooldown Hug: Given by U-1196 to AA 2153 after his Rage Against the Heavens below.
• Cool Old Guy: The veteran Red Blood Cells tend to be this, having survived and learned to handle the hellish landscape that is the host body. Shame they eventually have to be systematically executed and/or recycled after they reach a certain age, pass away naturally, or get irreparably damaged...
• Corpse Land: During the Gonorrhea chapter, AA 2153 makes an air delivery through an area littered with heaps of white cell corpses.
• Courier: The Red Blood Cells' one and only job. In spite of the fact that they constantly have to deal with death and dismemberment every time they make a delivery of life-sustaining oxygen and nutrients, and take away potentially toxic CO2, all the cells just keep complaining about how they never bring enough.
• CPR: Clean, Pretty, Reliable: Painfully averted. The body's ribs beginning to crack is actually the first indication that someone's attempting CPR.
• Crapsack World: Fitting for a spinoff about bad health, CODE BLACK deals with body functions failing left and right, cells struggling to keep pace with demand overload, Platelets working even younger than they already appear to be (their uniform is standard kindergarten wear, for crying out loud), and too many cells dying to count. Among other issues are the constant germ attacks with easily overwhelmed White Blood Cell forces, being gassed and killed seemingly at random thanks to smoking, and a constant lack of necessary goods while management continuously rations what little they have. Even the glamorous-looking hostess club of the Liver has its brutally dark and gritty reality...
• Cruel Twist Ending: The end of the first half for the manga, which is also adapted for the Season 1 finale of the anime, has everything looking up for the body following a major stint involving a near-fatal heart-attack, with the cells having dealt with most of the body's problems and the host having gotten a wake-up call that makes him stop destroying himself. Things look to be heading towards a case of Earn Your Happy Ending... which is quickly cut short by the main cell duo getting caught in a blood transfusion, followed by being transferred to a new body that somehow manages to be worse than the old one. Several times in the new body, cells transfused from the old body state that the crisis they've just weathered has been extreme and things should improve now, as the scare makes the body change its ways, but they don't.
• Cuddle Bug: Colchicine, an immunosupressant medicine, is depicted as a fluffy robot programmed to give a Cooldown Hug to every White Blood Cell it meets.
• Darker and Edgier: While the main series doesn't shy away from serious plotlines, CODE BLACK makes sure to remind the viewers that the life of an overworked body cell is fleeting and kind of miserable. The maturation of Red Blood Cells is portrayed as organs getting ripped out to make them more efficient oxygen carriers, and cells actually die instead of just switching their clothes, like in the main series. In Real Life tackling disease in chronically ill patients is arguably among the most grim things a doctor has to do (there needs to be care taken to end the superposited condition while also watching the chronical condition), so the basic approach is more than adequate, and something that keeps the manga as an (mostly) age-appropriate work.
• Darkest Hour: The last arc for the first host in the manga, and the final two episodes of the anime, have the body dealing with the greatest threat it will ever face: the body shutting down and potentially dying due to a heart attack. The event causes every single cell in the body to enter a state of despair and denial, desperately trying to believe there's hope for things to get better, even as things seem to only get worse. Thankfully, the body does get better, much better than even when the series started in fact, but it takes some serious outside help and major effort on the cells' part to force the body to stop destroying itself and earn themselves a genuinely happy ending.
• Deadly Gas:
  • Smoking cigarettes causes the blood vessels to fill with carbon monoxide, gassing, incapacitating, and rendering useless the hapless Red Blood Cells caught in its cloud.
  • Acetaldelhyde takes the form of black smog that makes everyone miserable.
• Despair Event Horizon: AA 2153 has one after AC 1677 sacrifices himself to save his life. He spends a long time depressed and locked away in his apartment, brooding about the meaninglessness of his work amidst the host body's self-destructive behaviour and neglect, and even tries to have the Spleen kill him.
• Deus ex Machina: Medications and procedures undertaken by the host body have this effect, seeing as they just about solve every problem that the body can't handle itself.
  • When the host suffers from erectile dysfunction, he uses Viagra, which is depicted as a swarm of robotic orbs that relax the muscles around the penis, allowing the red blood cells to properly form an erection.
  • Chapter 4 has Penicillin, depicted as a Kill Sat that helps the WBCs fight off the Gonorrhea.
  • Chapter 5 has a squadron of Steroid robots suppressing the immune system, and stopping the spot balding and hair follicle damage.
  • Chapter 6 has Butenafide Hydrochlorine washing away the first wave of ringworms.
  • Chapter 7 has the antibiotic Clarithromycin, depicted as a Spider Tank, helps the WBCs defeat the Helicobacter Pylori invading the stomach.
  • Chapter 10 has the coronary stent and defibrillator that revives the body after a heart attack.
  • Chapter 26 includes laser surgery, depicted as a Kill Sat that helps burn off the new blood vessels that threaten the retina, amputation of the gangrenous toe to prevent further spread of the damage, and intravenous insulin to help the body subsist despite the loss of pancreatic function.
  • Chapter 29 has nutrients being introduced directly into the bloodstream through IV when the body becomes malnourished.
  • Chapter 30 has the plaque buildup in the gums destroyed by a massive electric toothbrush.
  • Chapter 34 has the stomach being pumped in order to remove the sleeping pills the body ingested.
  • Chapter 39 has part of the lungs removed to excise a tumor.
  • Chapter 40 shows a cancer cell getting zapped by a targeted radiaton Kill Sat. However, when that fails to work and metastasis sets in, chemotherapy in the form of a flight of B2 stealth bombers begin indiscriminately carpet bombing the entire body. Then when Killer T Cell faces off against Cancer Cell, he's powered up by an immune checkpoint inhibitor in the form of a high tech belt that protects him against Cancer Cell's attacks.
• Driven to Suicide:
  • In Chapter 24, the overworked Beta Cells of the pancreas succumb to despair and hang themselves, causing the body to lose its source of insulin.
  • In Chapter 31, the second host attempts to commit suicide by taking an overdose of benzodiazepine (sleeping pills) in combination with alcohol.
• Dropped Glasses: AA 2153 loses his glasses at one point during Chapter 7, but he's too traumatized by his friend's death to even care. He eventually ends up fleeing the scene without bothering to find them. U-1196 finds the pair of glasses on the floor and picks them up, but she doesn't get to return them until the next chapter, when she reassures AA 2153 that his friend's death was not his fault.
• Drugs Are Bad:
  • The negative effects of longtime nicotine and alcohol abuse on the body's cells are shown in pretty gruesome detail.
  • For the cells themselves, AC 1677 learns the hard way why he shouldn't rely on caffeine to get him through his work shifts, as he nearly loses his life due to loss of strength when the caffeine wears off.
  • It seems like there's a degree of this aimed at the medicine the body is using, as various cells are uneasy about having to rely outside help for functions they feel they should be able to handle themselves. This finally get closer scrutiny late in the manga. Having delivered antidepressants, AA sees that the neurotransmitter using them to approximate normal function still seems miserable and in pain and decides to stop delivering drugs at all. On seeing varenicline's antismoking effects he starts to relent, and then upon returning to the neurotransmitter he finds that the antidepressants are still needed but have affected the glial cells, which have started taking better care of the neurotransmitter and things are in better shape.
• Due to the Dead: Apoptosis is depicted as Funereal Cannibalism, done by Kupfier Cells in the liver.
• Earn Your Happy Ending:
  • It takes the first host body having a heart attack in Chapters 9 and 10 for things to begin to get better. During that time, everyone gets overworked, but eventually, they realize that their home has been given a second chance at life, and intend to keep working so that it might stay like that, especially since this forces the host body to start taking care of himself better (eating a healthier diet, quitting drinking and smoking, adopting a more active lifestyle, etc). Sure, life for our two protagonists doesn't get any better after they're relocated by blood transfusion to a new, even unhealthier body, but the lives for every living cell in the old body are definitely looking up.
  • The second body goes through a lot more hardships, between depression, suicide via attempted overdose, and even the development of lung cancer. Chemotherapy may have stomped out the cancer but it's left a lot of collateral damage that has left it in a less-than-ideal state. However, towards the final chapters of the manga, things begin looking up again as the body starts making more healthy lifestyle choices and even receives the benefits of a clinical trial to prevent a recurrence of cancer, and the final chapter ends with the cells being able to look forward to doing their jobs safely in a healthier person.
• Eldritch Abomination: While individual bacteria are bad enough, plaque is an entirely different beast, as it's depicted as an endless amalgamation of billions of bacteria fused together into a single, horrifying entity that White Blood Cells have no hope of defeating on their own.
• Epic Flail: Macrophages here use huge flails, instead of the cleavers they use in the main series.
• Ethereal Choir: The Parasympathetic Nerves are depicted as a full choir who sing to help the body sleep and relax, as well as respond when the body is feeling intense emotions.
• Evil Only Has to Win Once: The Killer T Cell Captain says this almost word for word, explaining to the new Killer T Cell that they're constantly hunting and killing early-stage cancer cells because only one needs to escape them to potentially doom the body.
• Existential Horror:
  • AA 2153 has a number of despairing moments, wondering why all of them are even working so hard if the host body so steadfastly refuses to take care of itself, and especially when the cells realize that the host body is going through The Loins Sleep Tonight, leaving it unable to even fulfill the ultimate goal of any lifeform: reproduce.
  • A near-fatal heart attack is portrayed similarly to the Apocalypse.
  • Exposure to frequent crises causes various cells to question if they should even bother working for a body that willingly puts itself through undue amounts of stress. When medical intervention and drugs help sustain it, they also confront the possibility of their work being not as vital as they were trained to think.
• Edutainment Show: Played with. Like the main manga the series represents pathological processes quite well, especially those associated with societal influences like smoking and drinking alcohol. On the other hand, the life of the cells inside the host body(ies) is depicted as anything but fun.
• Fan Disservice: One chapter of CODE BLACK has U-1196 fighting off an army of extremely phallic monsters - Gonorrhea, to be precise. She gets overwhelmed and restrained, with her jumpsuit generously ripped off for the occasion... but she's covered in blood and about to be torn apart, with several other already dead or about-to-be White Blood Cells in similarly horrific situations. It's combined with Lecherous Licking, Perverted Drooling, and the Gonococcus moaning that they're "So lon-ely..." as if this wasn't bad enough.
• Foil: AC 1677 to AA 2153. Respectively, an easy-going slacker who has no illusions that any more hard work on his part will change the abysmal conditions of the body and even goes out of his way to shirk his duties, and a workaholic who will deliver his oxygen as quickly as possible, through thick and thin, and feels deep, personal guilt whenever things inevitably go downhill.
• Foreshadowing: We learn early on that the second body is also a chronic smoker, and after we meet the cheerful lung cell again in Chapter 33, he goes into a coughing fit that lasts after AA2153 leaves, despite having expressed his eagerness to start work as a full-fledged lung cell. The cell, K9999, is rejected from the lungs due to damage from cigarette smoke and eventually becomes cancerous.
• Friend or Foe?: The Killer T Cells are so overworked that they start to indiscriminately attack anyone that seems out of the ordinary. Unfortunately this causes them to identify the hair cells as enemies due to their fast splitting nature. Consequently they start attacking the poor hair cells, causing several of the hair shafts to come loose, resulting in hair loss.
• From Bad to Worse: Things just never improve in the hosts... Compared to all the bad stuff that happens to them, the Cosmic Plaything main series' host got off easy.
  • The first host: from the moment the host starts smoking again after 10 years of being off it, it just gradually worsens till he's having a heart attack and the whole system shuts down.
  • The second host is no better, struggling with sleep deprivation, stress, smoking and alcohol abuse, the many complications of diabetes, and requiring multiple surgical interventions to keep itself together. And then he attempts suicide via overdose, succumbs to depression afterwards, and when he starts making a recovery, he develops lung cancer.
• Gender Flip: CODE BLACK engages in quite a bit of this in relation to the original manga, as one way of portraying how different this story will be:
  • The main duo are still a clumsy, Naïve Newcomer Action Survivor Red Blood Cell and a serious but kindhearted One-Man Army White Blood Cell, but in this case RBC is a dorky, glasses-wearing boy and WBC is a busty and rather sexy Action Girl.
  • As a whole White Blood Cells are changed from an army of men to an Amazon Brigade.
  • The Ordinary Cells and Red Blood Cells pretty much swapped their gender ratio, with Ordinary Cells becoming 50/50 male and female while Red Blood Cells become a male One-Gender Race.
  • The anime adaptation extends this to even the narrator. The original is a high-pitched and cheerful teacher-like female voice, while this story has a deeper and much more serious commander-type male voice.
• Genius Loci: This time, the body in which the story takes place is of a male (has a penis) who makes some bad decisions, being stressed out and prone to unsafe sex and addictions.
• Happy Ending Override: A recurrent trope throughout the series — the body and the cells survive a crisis, but just when things start looking up, complications develop. It's a succinct portrayal of chronic disease and its complications.
  • The start of Chapter 11 seems to hint that, while the body recently had a heart attack, and things still might not be all that pleasant, with the intestines mad about the working conditions and polyps forming on the digestive tract, overall the conditions are improving... That is until U-1196 and AA 2153 are sucked out of their current host body by a needle, and transferred to a new, unhealthy body that was just as bad as the first host body during the beginning of the series, if not WORSE.
  • After the events leading up to Chapter 35, the second body is recovering from depression, is making efforts to quit smoking, and the reduced stress and better overall life it's enjoying is being reflected in the cells as the immune system also makes a recovery. Then we learn that a Lung Cell is rejected from work, and he's starting to develop into cancer from the body's long smoking history.
• Heroic Sacrifice: Done by AC 1677, pulling AA 2153 to safety and falling into the deadly gastric acid in his place.
• Hollywood Acid: While the human body's gastric acid is no joke in reality as it is in the manga, its effects are depicted as this, with all the sizzling, bubbling, and the horrific sights of cells' skin, muscles, and bones melting away into nothing that you've come to expect.
• Hope Spot:
  • Chapter 9. After a bout with gout, and reacting to the intense pain AA 2153 and the other cells cause the body, it seems like things might finally get better for them. Then the body has a heart attack and everything begins to shutdown, before it cuts to black. This is further played with in the anime adaptation, where the episode shows that the stomach ulcers have healed, the liver is recovering steadily, and the hair roots are even starting to grow back once more. This of course is shown so that it becomes all the more jarring when the heart attack actually does happen.
  • Part II opens up with the host body finally working properly, and everyone doing fine with no major incidents. It seems like all is going well...but then AA 2153 and U-1196 are transported into a completely different body, which is just as hellish, if not worse than their first.
• Hotter and Sexier: CODE BLACK, written by the person who brought you ecchi series like My Balls and Yuria 100 Shiki, gets plenty more risque than the other spinoffs: most cells get bigger and beefier to deal with their workload, the liver is a bustling red light district that gets visited, and we even get a mini-arc about Sperm Cells and their functions. The busty U-1196 fights plenty of germs while showing off her figure, and the rest of the Neutrophil division is similarly shapely and fit. The second host body's Neutrophils are just as servicey, with one being more petite and conservative topwise but having longs legs wearing thigh-high boots and garter straps instead of trousers to make up for it.
• I Did What I Had to Do: The Brain Cell Commander in the second body uses this to justify his cortisol order. Even if it does lead the body into depression and further increase the workload of all the cells, it was the only way to fight stress and prevent the body from trying to commit suicide again.
• I'm a Humanitarian: Apoptosis is shown as a Kupffer Cell eating a dead Red Blood Cell. While it's treated as a dirty little secret about the Liver, AA 2153 isn't upset by it in the least.
• Idol Singer: The Sympathetic Nerves are depicted as idol singers who use their music to help motivate other cells to keep working.
• It Is Not Your Time: AA 2153 falls into despair and tries to get the spleen to kill him, but the spleen cells refuse because he is still young and there is nothing physically wrong with him, so they order him to get back to work.
• Japanese Delinquents: The anime adaptation includes its own Platelet Cell Leader, except unlike Platelet Leader in the main story, this one has the looks and attitude of an aggressive delinquent, which one of her fellow Platelets explains as being a result of how overworked and stressed she is.
• Katanas Are Just Better: The White Blood Cell's default weapon is clearly based on a Japanese katana. They use them almost exclusively, until it's time to literally break out the big guns in the form of assault rifles and bazookas.
• Kill Sat: Penicillin is portrayed as this during Chapter 4, in the fight against Gonorrhea.
• Lighter and Softer: Of all things this applies to steroids. In the main series steroids are the focus of an apocalyptic prophecy due to destroying everything in sight indiscriminately and leaving the area in ruins. Here, they specifically and relentlessly focus on rampaging Killer Ts and the Helper T giving them orders, looking like remorseless assassins - but they simply restrain and bind the rogue cells, causing very little damage.
• The Loins Sleep Tonight: The host body has erectile dysfunction due to stress, and has to take sildenafil (Viagra) to correct this.
• Madness Mantra: "Eliminate them all!", said by the Helper T and Killer T cells as they go insane and rage destruction on the hair follicles.
• Manly Tears: Poor Killer T Cell Leader has this after the steroids suppresses him and the command center, and AA 2153 tells him he doesn't have to work anymore, in the wake of their rampage through a follicle.
• Man on Fire:
  • Glycation, the excessive absorption of glucose by Red Blood Cells, is depicted as them bursting into flames and shortly dying from their scars.
  • Oral mucosal cells in a mouth ulcer lesion are also depicted to be this. This time, the problem is AA2153 still wants them to sign their waybills...
• Meaningful Name: Works in both English and Japanese, for different reasons:
  • "Code: Black" is a hospital emergency that has different meanings in different countries. In the UK, it's used when a hospital is at maximum capacity. In Canada, it's for a bomb threat. In Australia, it's for a personal threat.^note includes violent patients, child abduction, and shooters
  • In Japan, a "Black company" means that the working conditions are dog-shit.
• Mentor Occupational Hazard: In what has to be a record, the main Red Blood Cell's mentor dies not a handful of pages after being introduced in the first chapter. This goes on to happen several more times to anyone who could be considered a mentor to AA 2153 as well as U-1196's senpai.
• Mistaken Identity: Spot baldness is caused by the stressed-out Killer T Cells mistaking the rapidly multiplying Hair Follicle Cells for Cancer Cells and attacking them.
• Monstrous Cannibalism: How apoptosis (cell death and recycling) is portrayed. When an elderly Red Blood Cell dies, one of the belly dancers at The Liver takes him behind a screen and eats his corpse.
• Mood Whiplash: Both the opening and ending for the anime are incredibly cheery and upbeat, showing all the characters happily going about their jobs. This is in heavy contrast to the sheer darkness of the actual content for each episode. The whiplash gets even stronger when it comes to especially dark episodes or major cliffhangers, since right when the story gets even more serious, it out-of-the-blue slaps viewers upside the face with the sudden lighthearted credits. On top of all that, the anime aired in the same cour as the second season of the main series.
• More Dakka: The Neutrophils' response when a problem gets too large for their already impressive blades is to start pulling out automatic rifles and bazookas.
• No Medication for Me: The dismay Red Blood Cell has about the body he's in having to rely on medication has shades of this, which hits a point when he brings a neuron antidepressants and finds that the neuron can do his job again, but is clearly still miserable and in pain. He decides he'll no longer deliver medications, but later changes his mind - the neuron's support cells have started taking better care of the neuron, so while he's still relying the device that represents the medication he's calmer and happier.
• Ms. Fanservice:
  • Regular white blood cells are depicted as an Amazon Brigade of sexy ladies with an Open Shirt Taunt built into their uniforms in the first body, and in the second body they have a short skirt instead.
  • Kupffer cells (the cells in the liver responsible for apoptosis) are shown as topless belly dancers.
• Must Have Caffeine: Played for Drama in Chapter 12. Red Blood Cells feel revitalized after their host body has an energy drink, but when the effect wears off, caffeine withdrawal sets in... And one Red Blood Cell collapses on the floor, pitifully begging for more caffeine. What's worse, he reveals to the rookies that energy drinks are the only way to find the energy to do their job in this ruined body.
• Must Have Nicotine: Both hosts are smokers. Both of them quit at some point in story, but for the second host, it's still a bit too late—he develops lung cancer.
• My God, What Have I Done?:
  • The cells' dedication to work leads them to improvise several workarounds when the body's own environment presents obstacles. It becomes a problem with neovascularization, as a Red Blood Cell's idea of tunneling through the retina to deliver oxygen presents the risk of retinal detachment and eventual blindness.
  • This implied to be the second host body's reaction after their attempted suicide.
• Mythology Gag:
  • Volume 1 of CODE BLACK shows the Red and White Blood Cells in a similar pose to the cells on the main series' first cover, except U-1196 is drenched in blood, while AA 2153 is deoxidized and carrying more than his own weight.
  • The presentation given to Red Blood Cells as seen in Episode 1 gives off an environment and atmosphere similar to C@W Prime, complete with music similar to one used in more peaceful scenes.
• Nice Job Breaking It, Hero: In their desperation to get oxygen to the retinas which are blocked off due to diabetes, the Red Blood Cells begin creating alternate routes via neovascularization. However, the Red Blood Cells are immediately called out by the Retinal Cells and Brain Cells because tunneling through a structure as fragile as the retina can cause it to fully detach from the eye and cause permanent blindness.
• No Name Given: Many of the background cells, and even some of the protagonists are not given proper alphanumeric designations. It's only until some omakes (end-of-chapter extras) do we get them, and even then, it's rarely said in the dialog proper, and many chapters after said character's first appearance. One has to assume it's intentional, to emphasize the cheapness of life and death for these cells.
• No-Nonsense Nemesis: The invasive bacteria present don't bother with Shonen villain antics the way they do in C@W-Prime, and are more like invading alien soldiers.
• Not So Stoic:
  • U-1196, upon seeing the corpse of her senpai during the mass funeral for the fallen White Blood Cells post-Gonorrhea attack, finds herself having to pull her cap over her eyes as she's overcome by emotion.
  • The kidney cells finally allow themselves to cry during the UTI arc (the kidney is a "silent organ" that doesn't set out a Distress Signal until it's nearly too late).
• Oh, My Gods!: Characters are prone to exclaiming "what the cell?" when surprised.
• Open Shirt Taunt: in the first body, White Blood Cells have their shirts open with nothing underneath to show their, uh, courage.
• Painting the Medium: CODE BLACK, a Seinen series, is in an adult male's body, depicted as a "black company"-like landscape. Hard lines and hazards abound, adult concepts like layoffs and hostess clubs are present, and most cells look noticeably older than their main series counterparts.
• Peaceful in Death: An old Red Blood Cell in Chapter 2, one of the lucky ones who went while enjoying himself at the Liver.
• Poor Communication Kills: In Chapter 5, this is how autoimmune diseases are portrayed, with the T Cell Command Center and the Killer Ts themselves overworked to the point of mistaking regular multiplying hair matrix cells as foreign bodies — with horrific, dramatic results. A poor Dendritic Cell just can't get them to listen as they cause hair loss.
• Pragmatic Adaptation: The anime goes the route of combining and rearranging various aspects of both manga hosts to be as if they happened all in the same body, shifting some events that happened inside the second host and moving them into the first, which also includes bringing characters like the Glomerulus into the story much earlier.
• Public Bath House Scene: The kidneys are shown to be a public shower, with the cells there depicted as cute girls with hoses. It's subverted, however, because it's neither fun nor relaxing for anyone involved. Red Blood Cells aren't even allowed to take off their uniforms and the kidney cells aren't allowed to talk to anyone to ensure maximum efficiency despite the fact that they just want to sit down and cry from being worked almost to death (the kidneys, like the liver, is a "silent organ" that doesn't let on how bad things are untill it's in full-on crisis mode). Their status as a Dwindling Party is made clear to AA-2153 and the reader (kidney cells don't replicate). The structure itself looks more like a cattle run than a public bath as well.
• Pyrrhic Victory: Basically the result of almost every single one of the body's immune responses. Sure, the immediate threat is dealt with and the body is saved, but it's almost always done with the last minute intervention of external medicines and surgical procedures. Even then, every battle inflicts more and more casualties and fatigue on the already weakened immune system, leaving them less able to handle future threats.
• Rage Against the Heavens: AA 2153, fed up with how the host body doesn't take care of itself, tries to make it listen the only way he can — by striking the body full force. The other cells join in and create pain, which finally gets the body to listen to reason and rest.
• Rapid Aging: The accelerated aging brought about by ROS (Reactive Oxygen Species) being absorbed by a cell is depicted as literally aging the affected cell several decades in a few seconds.
• Really Dead Montage: In the anime, AC 1677 gets one shortly after his Heroic Sacrifice in episode 10.
• Red Light District: The Liver is portrayed as this, with Hepatocytes depicted as attractive hostesses. Here, Red Blood Cells go to recover from alcohol exposure while also letting off steam, ironically sobering themselves up by imbibing hormones in a similar manner to drinking beer and smoking. Chapter 6 shows that the place has gone from Riches to Rags from the host's alcohol consumption, with the Hepatocyte from before looking like she has tuberculosis. As if it's to lampshade this point, the entrance of Liver is a homage of the entrance of Kabukicho, Tokyo's best known red-light district.
• Rousing Speech: AA 2153 gives one during the Gonorrhea attack in chapter 4, about how he will continue to do his job in spite of all odds, helping inspire the surviving Neutrophil forces to defeat the invaders. Of course, the Penicillin Kill Sat that came up behind him and made the bacteria vulnerable wasn't his doing, but U-1196 specifically thanks him for it in the next chapter anyway.
• R-Rated Opening: The first episode of the anime adaptation immediately starts off showing numerous dead and bloodied Red Blood Cells, leading into a scene of U-1196 fighting off bacteria while AA-2153 follows behind, which includes White Blood Cell outright slaughtering the antigens in incredibly brutal ways and Red Blood Cell going through an existential crises. All of this is for the express purpose of showing exactly what viewers are getting into compared to the main series.
• Ship Tease: Similar to AE 3803 and U 1146's moments in the main series, AA 2153 and U-1196 have some romantic moments. These are mostly her saving him and him acting smitten and Distracted by the Sexy in her presence; but in Chapter 2, when she catches him getting hugged and kissed on the cheek by a Hepatocyte, she acts irritated and jealous.
• The Siege: In Chapter 4, the White Blood Cells face off against a Gonorrhea infection. Both the Brain command center and the White Blood Cells themselves know it's a hopeless fight against an enemy that replicates faster than you can kill it, but they fight anyway, because that's their job. Thankfully, the body has the good sense to take some penicillin which helps the immune system fight it off for good.
• Shout-Out:
  • Staphtococcus bacteria look an awful lot like tyranid gaunts. Fitting, since staphylococcus is what causes flesh-eating disease and 'nids eat whole planets.
  • K-9999 has the same name as a character from The King of Fighters who is himself a Shout-Out to Tetsuo, who undergoes Body Horror mutations, loses his right arm and wears a ragged makeshift cape. Outcast from normal society, he decides to destroy it instead. The Reveal at the end of Chapter 39 has K-9999 looking almost identical to Tetsuo. They even try and fail to "nuke" him with radiotherapy and chemotherapy, and the former looks like a pillar of light like Tetsuo's psychic awakening.
• Sperm as People: Chapter 3 shows off the sperm cells, both in their "baby" forms within the testis themselves (being nurtured by the motherly Sertoli cell), and their "mature" forms for when they're in the epididymis and get released through ejaculation. After that, they're put in an Ambiguous Situation, with one Red Blood Cell telling AA-2153 that there's a good chance their hard work will be All for Nothing (though considering the host body is attacked by gonorrhoea shortly after, it's highly unlikely they managed to survive).
• Spoiler Title: The first chapter is named "Smoking, Germs, and the Beginning of the End". It pretty much tells from the start that this series is not going to have a happy ending.
• Spontaneous Human Combustion: How glycation is depicted. During the diabetes story arc, some of the red blood cells starts eating more than their fair share of glucose. One becomes portly before exploding shortly after reaching the pancreas, others we see trying to work with boiled-out eyeballs and 2nd-3rd degree burns all over their bodies.
• Stepford Smiler:
  • Just like in the main story, Macrophages have a major case of Dissonant Serenity, near-constantly smiling while they slaughter and butcher bacteria. However, with how heavily overworked the body is, the Macrophages here are constantly on edge, muttering about killing more bacteria as a Survival Mantra, any loud noise making them reflexively try to kill what made the racket, with one stopping just short of killing Red Blood Cell before apologizing in a strained cheery voice. Their smiles are also quite obviously forced in an attempt to stay positive in face of the immense stress.
  • AA 2153's first mentor is seen constantly smiling, which he reveals to AA 2153 is because he's doing his best to suppress his emotions, otherwise he'd crack under the stress. The latter does the same when he has his own newbies to look after and tries to take on their workload until his best friend does an intervention.
  • The liver and kidney cells, being "silent organs", have to keep up a facade despite their body's horrific working conditions. AA-2153 feels pretty awful for chewing out the liver cells once he's given a behind the scenes look.
• Suicide by Cop: Done by AA 2153 in a sense, since the Spleen is the authority of disposing of old and damaged Red Blood Cells.
• Suicide Mission: The Brain command center and the White Blood Cells both acknowledge that fighting the Gonorrhea infection is a losing battle, but they fight anyway.
• Super Serum: How caffeine is depicted. However, once it wears off, the cells dosed with it undergo intense widthdrawl.
• Surprisingly Happy Ending: With thanks to timely modern hospital treatments.
• Translation Matchmaking: The English title seems to evoke associations with Code Black, a TV series about an overworked and understaffed emergency room.
• Testosterone Poisoning: The Killer T Cells. Absurdly buff, hairy, and with the ridiculous levels of aggression and shouting to match, they make the Killer T Cells of the main series look like cannon fodder; fittingly, they show up during the chapter about spot baldness.
• Title Drop: The subtitle for the English translation of Volume 6 is Code Bleak.
• Ungrateful Bastard: Several cells mock the White Blood Cells and call them useless when they are trying their best to fight infections. They have to eat their words when they get rescued.
• Vapor Wear: All the female White Blood Cells wear their jackets partially unzipped/unbuttoned with no undershirt or bra.
• Viking Funeral: How the body pays its final respects to masses of fallen White Blood Cells, except without the "setting on fire" part. Just don't think too hard that their corpses are pus, and are going to exit through the urinary tract...
• Visual Pun: When the Leukyocyte's normal attacks fail to break down the purine crystal in Gout, Neutrophils start showing up with RPG's and assault rifles-literally breaking out the big guns.
• We Can Rule Together: The Gonorrhea say they know the White Blood Cells are not appreciated, and proposes they team up to get revenge on the rest of the body. The White Blood Cells say 'not a chance' and attack.
• Wham Episode: Chapter 9. The body suffers a heart attack and shuts down. Even the upper management in the brain declares that everyone can stop working now.
• Wham Line:
  • U-1196 gives one to herself at the end of Chapter 5 when looking down from a roof.
    My colleagues the other White Blood Cells... I can't see them anywhere?!
  • At the end of Chapter 17, U-1196 reveals to AA 2153 that the body has diabetes.
  • Chapter 31 reveals that the body has attempted suicide via overdose.
• Wham Shot: Chapter 14. After a battle, AA 2153 finds U-1196's sword all alone.
• World of Buxom: The first body. Most female cells we see have large chests, the largest of all belong to the Neutrophils and Macrophages. The Neutrophils especially are bursting out of their tops, even the few the that we see with them zipped up are still very filled out.
• World of Jerkass: Or rather, a Sour Outside, Sad Inside world. All the characters are stressed, tired, cranky, and have absolutely no time for pleasantries. Nobody laughs, nobody smiles — all of the cells just do as they are told and push everyone out of the way. The reason why everything is so grim compared to the origin series is because the body is in poor condition due to smoking, stress, and other bad habits which lead to germs infiltrating faster than normal. As such, the cells have no choice but to keep their heads down and work, and work, and work.
• World of Technicolor Hair: To differentiate the White Blood Cells in the next body, colored illustrations give them all bright hair colors like pink, purple, blue, green, or yellow.
• Yank the Dog's Chain: After nearly dying of a heart attack, the owner of the body cleans up and life for the cells slowly improves... Until a blood transfusion dumps the main characters in a new body that's even worse than the previous one used to be.
• You Are Number 6: As in the original series, characters are only ever referred to by their species, or their alphanumeric designation, such as AA 2153.
• You Don't Look Like You: Streptococcus-B (which causes necrotising fasciitis, AKA flesh-eating disease) is beefier and hunchbacked, with bigger claws, Glowing Eyes of Doom, and all their Combat Tentacles oriented backwards compared to the streptococcus-A bacteria encountered in Cells at Work!-prime, which is more humanoid.
• Zerg Rush: Athlete's Foot fungi are not very dangerous individually, and they are usually dismissed as minor annoyances... But U-1196 finds a flood of them, multiplying out of control due to the body's poor hygienic conditions, and they nearly overwhelm the immune system by numbers alone.
• Zombie Apocalypse:
  • Shown in horrifying effect in chapter 24, when red blood cells begin to suffer glycation en masse, which is depicted as them spontaneously combusting, burning off their skin and exposing the muscles underneath. They then revert into a berserk state and start attacking everything in sight.
  • Like in the original series, cancer is depicted as a highly dangerous affliction where even letting a single cancer cell escape can mean the death of the entire body as it proliferates uncontrollably. Even worse, cancer never truly dies and there is always a potential for it to return.

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