Manga / Caterpillar

From right to left: Imomushi and Hanakamakiri.

Caterpillar (キャタピラー) is a 2012 spinoff to Arachnid written by Shinya Murata and published on Young Gangan. It was illustrated by Isuka Hakozaki until his sudden passing in 2013 and then by Hayami Tokisada after a year-long hiatus. Tokisada became the main illustrator for the series from then on.

The story follows Miki "Imomushi" Inou, a young woman who was raised by an Organization of bug-like assassins after the murder of her sister Mika. To find the truth behind Mika's death, Imomushi moves into a battle royale on the cruise ship Ageha, where several other assassins have been convinced by a mysterious individual to hunt her for a reward while rich civillians bet on the outcome of the fights.

Although Caterpillar is mostly a prequel to Arachnid, it is best read afterwards for its development of recurring characters and because it involves spoilers for the latter, with both stories meeting and ending at the same point.

It ended on April 2018 at 97 chapters and was followed by a 2020 sequel titled Blattodea.

An official English translation of the series was made available on Square-Enix's Manga UP! app in July 2022 and on Comikey in 2023.

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This manga provides examples of:

• Action Girl: Imomushi, Kabutomushi and virtually any other female assassin in the story are quite capable in combat.
• All Just a Dream: Towards the end, Imomushi appears to finally have sex with Hanakamakiri but then wakes up and sees it was just a dream after all. Hanakamakiri had rescued her after Suzumebachi knocked her out and left her home with only a farewell letter.
• All Men Are Perverts: Other than Kumo, Riock and Kagimushi, most of the male characters in the story are sexual predators. This includes the Green Tree Ant triplets, who are just children but keep harassing women to "play doctor" with them.
• Almighty Janitor:
  • The Shidemushi are the Organization's Cleanup Crew and their original member is behind the Death Caterpillar game.
  • Osamushi and Kagimushi work as mangakas. To be specific, they're expies of Osamu Tezuka and Shotaro Ishinomori. So the God of Manga, of all people, killed enough people to be ranked first within the Organization.
• Always a Bigger Fish: The narrative exposition on paraponera clavata ants (aka bullet ants) in Caterpillar states they're so danguerous a group of army ants would avoid fighting a single one of them. This is likely Murata exaggerating though, and doesn't fit with how the army ant zombies are portrayed afterwards.
• An Arm and a Leg: Paraponera gets an arm blasted by an explosive, Unka loses both legs to a landmine and Hiratakuwagata gets her right leg chopped by Kabutomushi. The unsettling subtext is that all three characters have a common link to Dinoponera, insinuating she might suffer such a loss eventually: Paraponera is her father, Unka mirrors her failure to keep up with Paraponera and half the point of Hiratakuwagata existing in the story is implying Kabutomushi could've beaten Dinoponera with the Heracles blade.
• Animal Motifs: It's what most of the author's works revolve around. The personalities and skills of every character are compared in wild life trivia sections to the behavior of certain insects or arachnids. Given Imomushi is a protagonist, she is associated with many different species of caterpillars unlike how most of the characters only get one species of their bug.
• Anguished Declaration of Love: Hanakamakiri leaves a farewell letter to Imomushi after the Arachnid Hunt, stating he "betrayed" her to follow Suzumebachi's orders because he loves her and wants to ensure the Organization will never put a hit on her head again. Imomushi finds his reasoning nonsensical (she wouldn't resent him, she has no immediate enemies within the Organization anymore and he left her asleep and defenseless minutes before the rape zombies came knocking on her door) and just gets angry because he keeps skipping on their promise to have sex sometime.
• As You Know:
  • Chapter 25 begins with a recap of the current situation. Justified since the story had been on hiatus for nearly a year.
  • In the ending, Hanakamakiri explains in a letter to Imomushi what happened in the Arachnid Hunt after they left, which also serves as a recap to readers.
• Assassin Outclassin': Imomushi is hardly worried about being on a ship full of people trying to kill her. The Ageha nukes itself at the end of the story, but not only does Imomushi survive but she also takes 19 people away with her.
• Attempted Rape: The antagonists threaten both Imomushi and Hanakamakiri with rape every so often.
• Author Appeal: As with Arachnid, the story heavily features information about bugs taken from research papers. Physical and sexual violence are presented in a clearly fetishized way, and the page layout is very frequently formatted as a half-page panel, a Reaction Shot on the bottom right and a hook to the next page on the bottom left.
• The Bad Guy Wins: The original Shidemushi has Osamushi sacrifice himself to nuke the Ageha and get rid of various VIPs who were troubling the Organization in some way. A year later, by manipulating Alice to kill the Army Ant Queen, the Boss causes a rape zombie apocalypse meant to halve Japan's population and things only get worse to the country from there to the early chapters of Blattodea.
• Barbie Doll Anatomy: Thanks to its seinen perks Caterpillar had defined nipples on the female characters, but genitals are still out of the question.
• The Baroness: Akiho is a sadistic sexpot dominatrix in a nazi uniform who wants to ruin Imomushi's life for no good reason after already killing her sister.
• Beware My Stinger Tail: Sasori turns out to have a long mechanical scorpion tail attached to her back. How she hides that, especially in that miniskirt she wears, is anyone's guess.
• Big Bad: Yanagi "Swallowtail Butterfly" Akiho, the orphanage director who killed Imomushi's sister Mika and started the Death Caterpillar game to kill her too. But actually it's Mika herself posing as Yanagi.
• Big Bad Friend: Imomushi's sister Mika is in control of the Death Caterpillar hunt. She went insane and developed a split personality based on Akiho after being repeatedly raped and nearly killed.
• Bittersweet Ending: Borders on a Downer Ending. Imomushi survives the Death Caterpillar hunt but is unable to save her sister. One year later, she fails to kill Suzumebachi as revenge for him lying about her sister's death, but Hanakamakiri brings her back home. Hanakamakiri actually had a deal with Suzumebachi for Imomushi to be spared in exchange for him helping Alice become the new Boss, and feels so ashamed over it that he leaves to parts unknown. As Japan falls apart from a zombie apocalypse, a very annoyed Imomushi sets out to find both Hanakamakiri and Alice.
• Blade Below the Shoulder: Paraponera and Dinoponera have extendable needles inside thier arm guards, which have the immensely painful effect of their namesake ants' sting.
• Bland-Name Product: Kahen Rider. i.e., Transforming Rider instead of Masked Rider.
• Blue-and-Orange Morality: Characters such as Shidemushi and Suzumebachi firmly believe that the Boss is a visionary genius for nuking Japan on purpose, discarding dozens of their most skilled personnel in a bloody competition and later causing a Zombie Apocalypse to halve the country's population.
• Bolivian Army Ending: The story ends with Imomushi fighting off zombies in a massive outbreak to find Hanakamakiri and Alice.
• Bottomless Magazines: The Kumoito used by Kumo has an untold length of special spider thread inside it.
• Bowdlerise: Nazis are referenced with No Swastikas in effect during the transition from the magazine releases and the volumes.
• Breather Episode: Every once in a while there's a chapter that takes place during the period Imomushi and Hanakamakiri were getting to know each other.
• Bring My Brown Pants: Multiple female characters in the story wet themselves when they're scared for their lives. The author really indulged in this trope many times over the years for sooooome reason, and has freely admitted this on his Twitter profile (NSFW link).
  • In the beginning, Imomushi nonchalantly kills the kidnappers of a girl named Tomoe, who wets herself out of fear as she's still left tied to a chair.
  • Ichijikukobachi is left cornered and defenseless in front of Riokku, who looks ready to punch her head off but leaves her be when she offers her envelope trinket in fear. She ends up wetting herself and suffering a Wardrobe Malfunction at the same time, and nervously thinks to herself she's done being an assassin.
  • Togehamushi nonchalantly walks around naked like nobody can harm her spike-shooting body and takes on Riokku and Kagimushi. The latter doesn't want to resort to killing, so he throws a lightning-fast Megaton Punch just short of her face before the spikes can trigger. This scares her so much she falls on her back uncontrollably shooting spikes and suffering from incontinence.
• The Brute: "Sia ferox" Riock, who just recklessly throws Megaton Punch after megaton punch. It's a bit of a Running Gag for him to get countered and easily defeated but he never learns.
• But Now I Must Go: Hanakamakiri makes a deal with the enemy Suzumebachi so that by turning Alice into the new Boss and guarding her, Imomushi's life will be spared and he will be in a position to ensure no one in the Organization will ever target his partner again. He leaves Imomushi a farewell letter and disappears, thinking she wouldn't forgive him for such a "betrayal".
• Butt-Monkey:
  • Riock has an expanded role here compared to Arachnid, but all it amounts to is trying and immediately failing to punch people.
  • Most of Oki's screen time is spent on the background looking stupid. The only notable thing she does is deliver the Heracles blade to Kabutomushi after blackmailing the Green Tree Ants to make them help her, and even then she's briefly sexually humiliated before doing the same to them.
  • Himekuwagata's three partners also spend all their time just looking stupid in the background and are defeated in all of 5 seconds once they do take their chances at fighting Kabutomushi.
• Call-Forward: There are a number of scenes meant to echo later events from Arachnid — particularly those related to Dinoponera, curiously enough. Given what happens to her in Arachnid and considering those nods have a disturbing amputation subtext to them, Murata really seemed to want readers to be concerned about her...
  • Imomushi catching a knife with her teeth, referencing how she does that to Alice's and Dinoponera's weapons during the Arachnid Hunt.
  • When Jigabachi explains how he's using electrodes to paralyse Imomushi, he mentions the method can be improved to mind-control the victim, which later happens to Gokiburi in Arachnid.
  • One minor villain, Unka, holds a grudge agaisnt Paraponera for apparently tricking him into tripping a landmine, but Imomushi argues that Unka himself was too weak and just got left behind. This is similar to Dinoponera's backstory in Arachnid, where she fails to keep up with her father and is left to die alone.
  • Kabutomushi fights a shape-shifting girl who in her teen form looks suspiciously like Dinoponera and only defeats her by using the Heracles blade that, in Arachnid, she regrets not being able to use against Dinopo. Kabuto incapacitates her foe by chopping off her leg, similar to how Alice defeats Dinopo by forcing her to stab her own leg. The difference is that Kabutomushi refuses to kill her student but later insists Alice has to kill Dinoponera.
  • Kumo and Paraponera fight each other, mirroring the battle between Alice and Dinoponera in Arachnid. The difference is that Paraponera wins, which is intended to show how weak Dinoponera is compared to him.
  • As Imomushi is being beaten up by Dinoponera, an extra scene shows her thinking Dinopo is far too naive and childish to be able to beat a monster like Alice Fujii.
  • Imomushi saves Kumo but remarks he'll likely get himself killed anyway sooner or later. He forces his own pupil to kill him in the first volume of Arachnid.
  • The very final scene is a Call-Back to Imomushi talking to Alice back at the Arachnid Hunt, saying that the cause and solution for any troubles must be within oneself. It changes her lines a little so she tells Alice to carve her own path without depending on anyone, echoing Alice in the final Arachnid chapter saying a murderer like her cannot depend on other people.
• The Cameo: The scene with Inaho from Saikachi - Manatsu no Konchuu Kakutouki giving a lecture about bugs also features Moriyama, a minor character from Killing Bites, talking to her. He also briefly appears during one of the bug trivia scenes in Blattodea.
• Career-Ending Injury: Osamushi disappeared after losing control over his dominant arm, and in secret started producing derivative works of his own series. Ageha took advantage of his frustration to convince him to work for her in exchange for a shapeshiting artificial arm and eternal youth.
• Carnival of Killers: Imomushi is the target of the "Death Caterpillar" game at the Ageha cruise ship. The people attacking her carry a series of envelopes with details on how her sister Mika was killed and rich people bet on the outcome of the fights. However, the actual point of the competition is to nuke the ship and get all the VIPs inside killed.
• Cast Full of Crazy: Most of the characters involved in the story are deranged in some way or other.
• Casual Danger Dialogue: When Kabutomushi is about to fight Hiratakuwagata, she asks Gokiburi to bring Heracles to her and promises she'll be free from Pomario afterwards. Goki pulls up her cellphone and says she wants to record Kabuto repeating it just to make sure she won't go back on her word, but is driven away by Hirata's rampage.
• The Chain of Harm:
  • Kabutomushi is shown to be traumatized over being raised and trained by an unhinged child murderer, but as the current director of Pomario she's roughly half as sadistic and finds herself hunted by four of her disciples who hate her. They claim a lot of children still keep dying during training, even if not directly by her hand.
  • Gokiburi nearly starved to death as a baby after being abandoned by her parents and was trained by Kabutomushi, which turned her into a controlling Psycho Lesbian who wants to enslave people.
• Chekhov's Gun:
  • Gokiburi is shown to be carrying a cellphone with her when she tries to record proof of Kabutomushi making a deal with her. A while later she uses it to take nude pictures of the Tsumugiari triplets to blackmail them.
  • Arachnid had mentions of people and plot hooks that retroactively pay off in Caterpillar:
    • Kabutomushi mentions a "Hercules" weapon at one point in Arachnid. The prequel reveals it is a foldable double sword that belonged to the previous Kabutomushi.
    • Amenbo is a mere Villain of the Week in Arachnid, but it is established she's good friends with Imomushi. Way after a small appearance in Caterpillar, she's the one who gets Imomushi and every other surviving assassin out of the Ageha ship.
• Co-Dragons:
  • Paraponera, the number 2 hitman of the Organization, is Ageha's bodyguard and acts as Imomushi's archnemesis for the story. He ironically kills his boss to get her out of the way when it turns out she's actually Imomushi's sister Mika.
  • Osamushi, the number 1 hitman of the Organization, is convinced to work for Ageha in enchange for having his youth restored and acquiring an artificial right arm. He ends up letting himself be mortally wounded by his student Kagimushi to explode and accomplish the Organization's plan to sink the Ageha ship.
  • Himekuwagata is a friend of Ageha's who taught her to control her mental disorder. She's tasked with sinking the Ageha to kill all the civilians aboard and is fought by Kabutomushi towards the end of the story.
• Complaining About Rescues They Don't Like: Death Seeker Kumo is defeated by Paraponera fair-and-square but Imomushi saves his life. Later she has to drag his injured body out of the Ageha while he practically throws a tantrum begging her to leave him for dead.
• Crossover:
  • There was a short non-canon Hot Springs Episode between Arachnid, Caterpillar and Killing Bites. And a food contest comic, too.
  • Inaho Enoki from Vector Case File and The Island of Giant Insects appears twice to give fun facts about certain bugs, but she's merely a cameo with no effect on the actual plot.
• Dark and Troubled Past: Every single character in the cast has a miserable backstory, except for some of the villains who turned out the way they did in spite of a normal upbringing.
• Darker and Edgier: Compared to Arachnid, Caterpillar has more graphic violence and breasts are uncensored. Ironically, Choubu no Shinobi and Blattodea later made a point of being at least as graphic as Caterpillar in spite of moving back to a shonen magazine.
• Death Seeker: Kumo wants to die in a glorious battle for some unspecified reason and participates in the Death Caterpillar for that end. He is nearly killed by Paraponera, but is saved by Imomushi much to his chagrin. As she carries him out, she admits he'll eventually just get himself killed anyway.
• Defeat Equals Friendship: Riock is shocked when Imomushi beats him in a fist fight and pledges his loyalty to her.
• Depopulation Bomb: The story ends with a zombie outbreak put in motion so the Organization can halve Japan's population and rule over its remains.
• Died Standing Up: Paraponera dies from his injuries while dramatically pointing his gun on a helpless Imomushi. She stands up and moves out of the way upon realizing what happened, and is startled when the corpse pulls the trigger seconds later. The scene is adapted from the story's pilot, where said character dies on his first encounter with Imomushi.
• Double Standard Rape: Female on Male: Imomushi lusts over the much younger Hanakamakiri and repeatedly attempts to make him lose his virginity. He does love the tomboy back, so any instance of her being a little too forceful is Played for Laughs. He's too big and Imomushi gets afraid of him, so she hires a prostitute but then shoos her out when the girl tries dunking a large fleshlight on the boy instead of (forcefully) having sex with him. By Blattodea, they become the first Official Couple of the series (not counting Rin and Hanza in the spinoff Choubu no Shinobi) and nobody bats an eye at the age gap. Alice even hopes the couple can be happy together once the zombie apocalypse dies down.
• Double Weapon: Kabutomushi's Heracles is revealed to be a giant double sword that can fold to slice people.
• Dramatic Irony: The encounter between Imomushi and Dinoponera at the Arachnid Hunt seen in Arachnid is reprised in its entirety, if only to point that she actually wasn't as tough as her father and to keep readers wondering just what became of her after she got raped offscreen by the ant-zombies.
• Dual Age Modes: Himekuwagata initially appears as a child who represents the Dorcus rectus species, but she suddenly grows up and starts calling herself a curvidens. Then she finishes her transformation into a Chainmail Bikini-clad titanus adult. Her three forms are actually split personalities who consider each other sisters and are all conscious at the same time.
• Enfant Terrible: The little Weaver Ant triplets are obsessed with trying to force women to "play doctor" with them. Gokiburi, who at this point is around 14 years-old, turns the tables on them by stripping them and taking pictures of their dicks to use as blackmail material.
• Evil Old Folks:
  • Jigabachi, the Mad Scientist who develops devices for torture and brainwashing.
  • Unka, an Old Soldier turned into a cyborg assassin after he lost his legs to a landmine.
  • Osamushi, the in-universe Osamu Tezuka who has killed enough people to be ranked the best assassin in the whole Organization, even above Paraponera. However, he's rejuvenated at the point he antagonizes Kagimushi.
  • The original Shidemushi, who was hired by the Boss after losing everything in WWII and returns the favor by sacrificing himself to nuke the Ageha to get rid of a number of VIPs, with several innocent civilians caught in the explosion.
• Extremely Short Timespan: Prologue and flashback chapters aside, Caterpillar takes place in a single setting over the course of a single day. The last couple of chapters are a time skip into Arachnid's everlasting afternoon and then its aftermath.
• Face Death with Dignity: When Osamushi is mortally wounded by his pupil Kagimushi, he actually takes it very well because by exploding into a mushroom cloud he gets to be the one who terminates all the civilians and politicians within the Ageha in service of the Boss. He tells Kagimushi to flee and calmly dies singing the Astro Boy theme song.
• Fan Disservice:
  • There are multiple scenes of girls being raped by men on-panel, which was something the author was held back from portraying in the previous Arachnid series due to censorship standards of the shonen Gangan JOKER magazine at the time.
  • To make Kinohadakamakiri think he's gone evil, Hanakamakiri starts lying about how he's been following Imomushi around just to chop her limbs off and turn her into a literal nude caterpillar for sex slavery purposes, which is portrayed in a gruesome Imagine Spot.
• Fanservice: In this series, female characters are shown in various states of undress constantly from Arachnid onwards. Caterpillar takes it one step further by actually including uncensored nudity. What is intended as fanservice in the story can often be disturbing, however, as it tends to be accompanied by (either attempted or successful) rape or sexualized violence and humiliation.
• Final Boss Preview: Paraponera is Imomushi's Starter Villain and Final Boss. Kinohadakamakiri and Kumo come across Paraponera in the Ageha before Imomushi does and both men job to him one after the other just before she arrives.
• Gatling Good: After Paraponera launches the blade on his prosthetic arm, he shoves the stump through a crate and it neatly attaches itself to a gatling gun contained within.
• The Ghost:
  • Alice Fujii makes a cameo in a bug funfacts scene about roaches, and later her exploits in the Arachnid Hunt are mentioned by Hanakamakiri when he explains she's supposed to be crowned as the new Boss of the Organization. She's only briefly seen in person on a flashback of the time Imomushi encouraged her to fight for herself.
  • The assassin ranked 8th in the Organization is a man codenamed Tonosamabatta, or Migratory Locust. He's the one guy who never appears throughout the story, but one bonus poster shows he's supposed to look like how Oda Nobunaga is portrayed in Choubu no Shinobi.
  • The Organization's Boss is never seen in-person but the story, at a point it is a prequel, reveals her identity and some of her background in a chapter published after her big reveal in Arachnid happened.
• Given Name Reveal: Kabutomushi's given name is revealed to be "Ran" in her backstory.
• Glad-to-Be-Alive Sex: Even though Hanakamakiri promises to spend a night with Imomushi after they return alive from the Ageha ship, a year goes by and nothing happens for no real reason — with only a bait-and-switch dream scene of the two having sex at most. Imomushi then gets frustrated at Hanakamakiri departing for betraying her in a way she doesn't give a damn about and starts shouting she'll find and fuck him even if she must resort to rape, mirroring what happens between Goki and Alice in Arachnid.
• Gorn: The story features a few gory scenes, including a closeup of a person's crushed head in one of the last chapters. Arachnid, in contrast, had to censor a scene of Sasori dissecting her own parents on the transition between the Gangan JOKER magazine and volume publications.
• Gratuitous Rape: Most of the characters in the Arachnid series are sexual predators, victims of rape or both. In Caterpillar, Imomushi, Hanakamakiri and a few more female characters all have Rape as Backstory and the matter is shown more graphically since it was a seinen publication. The story even ends with Imomushi expressing a desire to rape Hanakamakiri in a comical way, in the middle of a rape zombie apocalypse.
• Guns Are Worthless: Some characters do use guns, but hardly get any use out of them and soon completely forget they exist as focus is shifted to the assassins' weird insect-themed abilities and weapons. In the end, after much clowning around with gatling gun fire, Paraponera finally has Imomushi at his mercy but runs out of batteries and dies on the spot, his body only pulling the trigger after she had moved out of the way.
• Hair Antennae: Oki has a pair of antennae to befit her cockroach theme. They even move while detecting movements around her. Oddly enough, she spontaneously gained those antennae just by identifying with a cockroach she saw back when she was an abandoned baby in a thrashed house.
• Hammerspace: Hanakamakiri often pulls his scythes from out of nowhere, even when he's naked and seemingly unarmed. Then there's Sasori and her mechanical stinger tail. She doesn't even wear a lab coat in this story to serve as an excuse for why it can be concealed.
• Heel–Face Turn: Both Riock and Kumo end up fighting on Imomushi's side after antagonising her.
• Herbivores Are Friendly: The assassins introduced in this spinoff mostly have the traits of herbivore bugs, but this only serves to give them weirder ways of killing people.
• Hot Springs Episode: The Febuary 2015 short crossover between Arachnid, Caterpillar and Killing Bites had Alice, Gokiburi, Imomushi, Hanakamakiri, Hitomi and Oshie hanging out at a hot spring.
• I Know Mortal Kombat: Riock is a "Kahen Rider" fan who took from that show an idea of surviving through brute force alone and uses "Rider Punch" as his signature move.
• I Love the Dead:
  • When the Weaver Ant triplets ask Jigabachi to let them "play doctor" with a paralyzed Imomushi before he does anything to her, he comments them preferring a living woman instead of a corpse is "an unusual fetish". They reply that no, it's not that unusual...
  • The original Shidemushi, who's a decrepit old man, is said to sometimes request female corpses from his subordinates for... undisclosed reasons. He takes the apparently dead Mika and puts her into some kind of bacta tank clearly not to revive her, as he's shocked when she springs back alive and starts choking him.
• Idiosyncratic Episode Naming: Both Arachnid and Caterpillar are One Word Titles, and named after animals. Each chapter is named after dialogue or monologues said in them.
• Irony: In the ending, Suzumebachi remarks that the Boss is sparing no effort to find and kill an enemy "beyond their imagination". Then in Blattodea it turns out it's just Serena Cervantes, a recurring character from the author — specifically a version virtually identical to the introduced to Himenospia three months after said quote from Suzumebachi. So while even into Blattodea the characters have little idea of who Serena is, readers already had the full picture of her personality and motives since Himenospia had just ended.
• Japanese Beetle Brothers: Kabutomushi is a girly, intense and incredibly strong rhino beetle lady who faces a quartet of her students who are themed after stag beetles. Moreover, Kabuto gets to show off a Heracles beetle-themed weapon after her enemy upgrades to a Dorcus titanus stag.
• Late-Arrival Spoiler:
  • Chapter 59 of Caterpillar, first released while Arachnid was nearing its end, spoils the major plot twist of Yoriko being the Organization boss. The last two chapters also give the gist of what happened over the course of the Arachnid Hunt.
  • Arachnid and Caterpillar were officially translated to English in 2022, several years after the end of their respective runs. The Caterpillar translation went past chapter 59 while Arachnid was still on chapter 31, and then finished in 2023 while Arachnid was still on chapter 53, indeed spoiling everything about Arachnid to Western readers.
  • Avoided when both were published on the Comikey website: Caterpillar paused on chapter 93, the ending of the prequel part, without even a release date for the next chapter until the ending of Arachnid was uploaded.
• Little Miss Badass: Most of the female characters in the story, like Imomushi and Kabutomushi, were already abnormally powerful and very dangerous as children.
• Load-Bearing Boss: When Osamushi dies, he detonates into a nuclear explosion that obliterates the Ageha ship. Imomushi manages to escape with Amenbo's help and brings along every other assassin that managed to make it to her. All the other guests and civilians die in either horror or blissful ignorance.
• Mad Scientist: Jigabachi, who develops brainwashing devices and installed the mechanical tail on Sasori.
• Make Some Noise: Paraponera suddenly screams at Kumo with great force to distract and (try to) shoot him dead. He's essentially "stridulating" like ants do, which is treated as unique to him and Dinoponera even though many other bugs can do that.
• Mercy Kill: Caterpillar finds Paraponera's raping one of his targets and shoots her dead from out of pity.
• Must Not Die a Virgin: Before going into the Ageha cruise ship, Imomushi had been trying to convince Hanakamakiri to have sex with either prostitutes or herself while saying it'd be a shame if he happened to die a vigin.
• Near-Villain Victory: Paraponera defeats and nearly kills Imomushi during their rematch, but dies from his injuries while aiming at her.
• No Celebrities Were Harmed: Two high-ranked assassins based on Osamu Tezuka and Shotaro Ishinomori are introduced in this prequel.
• Not Just a Tournament: The Death Caterpillar is actually a "Pest Control" meant to weed out traitors and kill wealthy civilians and politicians who are obstacles to the Organization. At the end of Caterpillar, the Ageha ship is flat-out nuked to cinders.
• Offscreen Villainy: It is mentioned that Kabutomushi isn't much better than her master and most of her students die during training. However, this is never shown to the reader. All examples given of her dealing Training from Hell on her students are either Played for Laughs or justified on her part.
• Older Than She Looks:
  • Kabutomushi is heavily implied to be an adult in a teen's body. How and why she's like this isn't fully explained even in the prequel, but it might have something to do with her cyborg-esque enhancements.
  • Osamushi got rejuvenated at some point after he retired from the manga industry and disappeared.
• Once an Episode: The National Geographic commentary on bugs happens on nearly every chapter, bordering on self-parody when used in response to a character doing something mundane or silly.
• One-Word Title: Arachnid, Caterpillar and Blattodea are the names of the main entries in the series.
• Only Sane Man:
  • Kumo is noted for being unusually professional among his peers, but even then he enters the competition just looking to die in combat.
  • Kabutomushi is a ruthless Sadist Teacher, but she's also surprisingly nice and reliable. Particularly compared to her mentor who nonchalantly killed anyone he thought to be weak, including children.
  • Kagimushi seems like a rather pleasant old man and didn't treat Imomushi badly while training her, which is why it's surprising to see him appear as a threatening antagonist later in Blattodea.
• Orphanage of Fear:
  • The Orphanage Miki/Imomushi and Mika lived in. The employees beat Miki up for making trouble at school and the director's daughter, who goes on to become the main villain, sexually abuses Mika for years in exchange for Miki not being sent to a reformatory.
  • Ran Kabuto was raised in Pomario, an orphanage that is a front for the Organization to train child soldiers and in which her once-beloved master Hercules killed her best friend for kicks. Once the beetle girl takes his mantle as Kabutomushi, she ends up treating her own pupils only slighty better as Himekuwagata accuses her of letting most of them die during training.
• Perception Filter: Nanafushi's gimmick as a stickbug-like assassin is being supernaturally ignored by people around her. This illusion can break if she loses focus, such as when Hanakamakiri glares at her general direction acting like he could see her when he actually couldn't.
• It's Personal with the Dragon: Paraponera earns this relationship with Imomushi when he fatally injures her sister Mika while Imomushi was trying to make peace with her.
• Playboy Bunny: The hostesses at the Ageha all wear bunnygirl costumes. Kabutomushi and Gokiburi do too, to try to blend with them while infiltrating the ship.
• Post-Climax Confrontation: After the Death Caterpillar game is done with, the story skips to a year later in the Arachnid Hunt where it is known just why Imomushi is enraged with Suzumebachi. He sics Dinoponera on her, and the battle between Imomushi and Dinopo is reprised panel-by-panel as it was in the original. After Suzumebachi knocks Imomushi out and Dinoponera leaves, it is revealed Hanakamakiri came to retrieve her partner, and that he and Suzumebachi made an agreement of eventually forcing Alice to take over the Organization.
• Prequel: The first 93 chapters take place a year before Arachnid. From 94 on, there's a time skip into the Arachnid Hunt and the story becomes a P.O.V. Sequel just before it ends with a Sequel Hook.
• Production Foreshadowing: Chapter 25 starts with an As You Know recap that suggests bug-themed assassins have been around since ancient times. The 2017 manga Choubu no Shinobi establishes itself as a prequel in the Sengoku period by reusing the group shot of the assassins during a similar narration. Oddly enough, the samurai character in the panel got redesigned for the latter one.
• Quest for Sex: Arachnid and Caterpillar end with Alice and Hanakamakiri leaving their partners Gokiburi and Imomushi. The latter two swear to find and shag them even if they need to rape them.
• Quirky Miniboss Squad: A colorful quartet of Kabutomushi's stag beetle students comes to challenge her out of anger over her abusive training. Half of them barely even get any page time.
• Rape as Drama: Sexual assault is a constant in Caterpillar, with several female characters having attempted or successful rape in their backstories and a few becoming unhinged and attempting to get others raped as well.
• Rape Is a Special Kind of Evil: A lot of the bug assassins cement themselves as evil by attempting to rape someone or get them raped by someone else. They are also the ones most likely to fall victim to some Cruel and Unusual Death later... except for Kinohadakamakiri, who is among the worse of them due to his abuse of Hanakamakiri but comes to respect the boy's fighting prowess and, despite losing to Paraponera, survives the conflict with only some injuries.
• Rape Leads to Insanity:
  • Ichijikukobachi was gangraped when she was 14 and murdered her assailants in retaliation. She has nervous breakdowns while fighting and acts as if she's raping people with her drill weapon.
  • Mika was repeatedly tortured and raped by Akiho at the orphanage until she developed a split personality based on her own abuser. After nearly dying, being raised as an assassin and finding that her efforts to let Imomushi have a normal life were for naught, she started the Death Caterpillar to get her sister raped to death too.
• Retcon: When Imomushi gets worfed by Dinoponera at the Arachnid Hunt during Arachnid, she thinks to herself that Dinopo seems even stronger than her father Paraponera. By the time that scene is replayed in Caterpillar, though, readers have seen Dinoponera get humiliated by Alice and Sasori, how frail she is deep down and how Paraponera fought to his last breath against Imomushi and nearly killed her. The scene is extended so Imomushi takes back her statement and doubts Dinoponera will stand a chance against Alice.
• Rule of Symbolism: Dinoponera being written out of Arachnid like garbage by Sasori getting her raped a ton of times by zombies wasn't enough — this entire spinoff is not so subtly meant to discredit the idea that she is strong at all through parallelism with other characters. It's implied she deserved to get abandoned by Paraponera like Unka did, that she would've lost to a Heracles-armed Kabutomushi like Himekuwagata did and that she's a coward for not fighting to the bitter end like Paraponera. This all builds up to a retcon where a monologuing Imomushi takes back her opinion that Dinoponera is stronger than her father, and later in Blattodea she tells that to the girl's face while humiliating her. Furthermore, Unka, Himekuwagata and Paraponera all end up amputated from their failures. This leads to Blattodea very conspicuously directly associating Dinoponera with a zombie girl that Alice has mutilated.
• Saved by Canon: Characters like Imomushi, Hanakamakiri, Kabutomushi, Sasori and Kumo are known to still be alive by the events of Arachnid. Everyone eventually escapes from the Ageha on a a ship owned by Amenbo. Paraponera is the only character hit by the opposite trope, as it was a Foregone Conclusion that Imomushi would kill him. The twist is that she pretty much loses to him but he ends up dying from his injuries before he can finish her off.
• Series Continuity Error: When the series resumed a year after the passing of Isuka Hakozaki, Imomushi was first seen in chapter 26, nonchalantly walking around topless while holding the rest of her costume. Because Imomushi hadn't been stripped to that extent by Sasori in the previous chapter she was in, this page was edited for the volume 4 version and afterwards she fights Unka while wearing her usual strapless crop top and panties.
• Sequel Hook: In the ending, Suzumebachi and Hanakamakiri plot to make Alice the new Boss of the Organization in order to counter an unknown threat that had been infiltrated among them the whole time.
• "Shaggy Dog" Story: Mika was blackmailed into becoming a sex slave for Ageha in exchange for Imomushi not being sent to a reformatory for her delinquent habits, and after a lot of rape and torture she was finally killed. Imomushi gruesomely avenged Mika, but ended up caught by the Organization and turned into an assassin. The Not Quite Dead Mika is revealed to have hated Imomushi the whole time as she suffered alone, even more so when it was all in vain. She tries killing Imomushi in revenge but can't bring herself to do it and ends up killed herself by Paraponera, meaning the whole mission was All for Nothing for Imomushi too. Imomushi fails to kill Suzumebachi for lying about Mika's fate, only for him to later be killed in unrelated circumstances. Furthermore, the zombie apocalypse means everything would've gone wrong for Imomushi anyway even if she didn't become a hitwoman.
• Shameful Strip:
  • The Weaver Ant triplets undress a restrained Imomushi intending to rape her before Jigabachi experiments on and kills her, but the kids start beating each other over who gets to molest her the most. This allows Imomushi to struggle and pull the syringe that's paralyzing her.
  • Megumi is asked by the Weaver Ant triplets to strip herself in exchange for them carrying Kabutomushi's secret weapon for her. She does it while frowning at the ceiling in embarrassment, but gets angry when they make fun of her small chest and then strips them too to take pictures for blackmailing them.
• Shameless Fanservice Girl:
  • The series normally goes for eroticizing girls being embarrassed about their body sizes or nudity, but Imomushi is a consistent exception. She has a few scenes where she ends up fighting or casually walking around while nude without any shame, and there's even a time where she sits down naked and complains about life to her enemy Sasori before fighting her.
  • Togehamushi has the power to grow long spikes all over her body and doesn't bother wearing anything but a robe because of it. She has a gloomy demeanor and acts like no man or anyone else could ever touch her, but amusingly glomps Riock's head with a warm smile to impale him repeatedly without actually killing him.
• Shout-Out:
  • One page shows Ageha in a Nazi military uniform striking the pose from the cover of Ilsa, She Wolf of the SS.
  • Chapter 40 shows Kabutomushi holding a cellphone designed after the Kabuto Zecter.
  • Chapter 45 has Inaho Enoki from fellow bug manga Vector Case File discussing bark mantises. Chapter 46 has the in-universe equivalent of Kamen Rider creator Shotaro Ishinomori talking about crickets. Those interview scenes are based on the ones from Baki the Grappler, as are the ones featured in Killing Bites and other Fighting Series by Murata.
  • Osamu Tezuka is also portrayed as a master assassin, with multiple references to series like Astro Boy, Black Jack and Phoenix in his backstory and abilities.
• Skyward Scream: Imomushi screams in rage and despair for four pages after her sister dies for real.
• Slept Through the Apocalypse: When Imomushi is taken home after Suzumebachi knocked her out, she wakes up and is dumbfounded by the ongoing sex zombie apocalypse happening outside her apartment.
• Somewhere, an Entomologist Is Crying: The series greatly exaggerates insect qualities for the sake of justifying the superpowers of the assassins.
• Split Personality: The story features a split personality disorder that changes people's appearances, to the point of them aging back and forth as seen with the Kuwagata "sisters".
• Spike Shooter: Togehamushi's entire body, eyeballs included, grows long spikes when she's overly emotional or needs to defend herself. The spikes are nearly instantaneous and have apparently protected her from bullets, leaving her too cocksure that nothing can harm her in a straight fight.
• Spotlight-Stealing Squad: Kabutomushi gets a notably high amount of focus compared to the rest of the cast while fighting a group of her pupils in scenes that are mostly detached from the main plot of Caterpillar.
• Stealth Sequel: At first, all the reused elements from Jackals in both Arachnid and Caterpillar could be seen as mere production throwbacks. Then Roxy and her Alligator blade are directly mentioned in Kabutomushi's backstory, establishing the two series do share the same setting.
• Strong Ants: Some antagonists are ant-themed and have some of the associated quirks.
  • Paraponera is an acrofatic man who survived a grenade exploding on his face and fights ferociously until he kills his prey or is killed himself.
  • The Weaver Ant triplets have abnormally high strength and a device on their palms that lets them easily hold anything over their heads.
  • Dinoponera comes equipped with poisoned stings and is shown to be greatly strong, fast and resistent, even if the story retcons her as being inferior to her father.
• Take That!: One chapter has a cameo of Inaho Enoki from Vector Case File as she gives a lecture about misinformation in entomology. She's asked if cockroaches can evolve and become huge and agressive, and replies that's 100% false.
• Thou Shalt Not Kill: Kabutomushi refuses to kill needlessly after her master, a mad man who believed himself entitled to kill anyone he wished because of his strength, killed her only friend. As such, she has a blank ranking within the Organization despite bragging about being their strongest hitwoman. This was not mentioned even once in Arachnid, and in fact contradicts the things she goes on to do in that story with no justification: she attacks enemies with clear killing intent, tries to convince Alice to kill Dinoponera (contrasting how she spares Himekuwagata, a Dinoponera lookalike, in this prequel) and ends up killing the Boss without batting an eye to save Alice. Blattodea then tries to patch this half-assedly by showing everyone else she smashed actually survived and insisting Alice was the one who killed the Boss when she clearly wasn't.
• Toplessness from the Back: When the Weaver Ant triplets ask Gokiburi to undress in exchange for them carrying the heavy Heracles for her, she's seen from behind removing her bunnygirl costume while pouting and staring off at the ceiling.
• The Ugly Guy's Hot Daughter: The cutesy Dinoponera to Fat Bastard Paraponera, but she's adopted.
• Unsettling Gender-Reveal:
  • Imomushi tries to bathe with Hanakamakiri soon after meeting him, and is surprised to see Hana is actually a male crossdresser. Although Hanakamakiri tries to beat her up in response, afterwards he doesn't mind that she keeps treating him as a man.
  • Hanakamakiri is forced to lift his dress as a way for Imomushi to tell him apart from a master of disguise. He is really embarrassed afterwards as Kumo assumes he's a Villainous Crossdresser and Riokku starts bugging him about it out of innocent curiosity.
• Use Your Head: Imomushi's signature technique is to nail her shoes to the ground, dodge an attack by bending backwards and then catapult herself head-first on enemies. She sometimes switches the headbutt for a Megaton Punch instead.
• What Happened to the Mouse?:
  • There are a couple of minor villains that don't escape the Ageha ship with Imomushi but aren't shown getting killed in the explosion either.
  • The story prominently features Dinoponera fighting Imomushi at the Arachnid Hunt, but doesn't adress her terrible fate seen in Arachnid at all. There's also no word on what happened to Amenbo and Riokku when the zombie apocalypse broke out.
• The Worf Barrage:
  • Every time Riock tries to punch somebody, he gets either blocked or countered and then is knocked out silly in one move.
  • Kabutomushi has a signature Spam Attack with her halberd that blows enemies away. When she does it on a cramped corridor to kill Imomushi, she crushes a pipe on the wall and floods the place, so then both women flee for their lives and stop fighting. When she tries it against Ookuwagata, the girl simply catches the blade with her mandibles.
• The Worf Effect: Riock is a towering and muscular Scary Black Man but this trope is all he is used for. New enemy shows up, he tries to punch them, fails and gets knocked out. And yet even he defeats more people on and off panel than Gokiburi does!
• Worf Had the Flu: Kabutomushi gets the snot beaten out of her by Hiratakuwagata until Gokiburi and the Tsumugiari triplets arrive with the Heracles, a giant double-sword which can fold to crush people like the jaws of an alligator. From then on, Kabutomushi easily turns the fight around and defeats Hiratakuwagata by chopping one of her legs off. The entire fight is a Call-Forward to Kabutomushi getting owned by Dinoponera in the Arachnid Hunt and regretting not bringing Heracles for the event, implying she could have killed the ant-girl with it.
• You Killed My Father:
  • Paraponera mortally wounds Mika right in front of Imomushi and she barely wins the ensuing fight. It is then seen this is why Imomushi intended to kill Suzumebachi at the Arachnid Hunt, as he knew Mika was alive all along but never told her and in fact kept blaming her over the girl's supposed death.
  • Imomushi asks Dinoponera if she wants revenge for her father Paraponera's death, but the ant-girl seems unbothered and just says he must've died honourably against a Worthy Opponent.
• You Have Outlived Your Usefulness: The Ageha was meant to be sunk with everyone inside despite over 30 of the most formidable hitmen of the Organization being involved in the conflict, in an attempt to dispose of traitors. But apparently none of them were, and among them only Kabutomushi could be seen as expendable due to being a Token Good Teammate who wants to mantain her rule over Pomario. Imomushi saves 19 fellow assassins on her way out and also gains a grudge against the syndicate for how they ruined her sister's life, making Hanakamakiri worry that the Organization could kill her. This leads him to make a deal with their enemy Suzumebachi to ensure Imomushi's safety.
• Zombie Apocalypse: An outbreak of rape-zombies devastates Japan at the end of the story.

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