''Apocalypse no Toride'', or ''Fortress of the Apocalypse'' by Kuraishi Yuu, follows 4 inmates at the Shouran Juvenile Reformatory: the falsely accused Maeda Yoshiaki, cool but dangerous Masafumi Yoshioka, the strong and silent but fair Iwakura Gou, and the smart-mouthed genius Yamanoi Mitsuru. Upon arriving at Shouran on false murder convictions, Maeda Yoshiaki would rather be anywhere on earth, but when a van full of infected zombies crashes into the prison and its passengers begin to attack the guards and inmates, Maeda and his cellmates begin a fight to the death to stay alive amongst the infected from the outside world and the anarchy that arises within the prison. Eventually forced to leave the prison's walls of safety, the boys of Cell 4 find horrors in the ravaged cities beyond what they could have ever imagined.
!!This manga provides examples of:
* AbusiveParents: Mitsuru's mom was mentally unhinged and would lascerate his hands if he scored anything less than 100% on all of his exams. [[spoiler: Mitsuru still cared deeply enough for her to murder a social worker who'd come to get him out of such an unsafe household.]]
* AnArmAndALeg: [[spoiler: Maeda]] thought they were going to kill him, but they were simply planning on cutting off the limb that was bitten by the Bokor.
* AndThenJohnWasAZombie: Maeda's certainly infected, showed the increased regeneration and the ability to control the mindless zombies. The change wasn't full yet though, he still had only 1 pupil... and his genitals. [[spoiler:Not so much for Yamanoi, who was later revealed to be infected when he was earlier scratched by an infected days ago. But he managed to retain what is left of his humanity long enough to saving his friends in a HeroicSacrifice.]]
* ApocalypseAnarchy: Type 2, and only because it happened ''fast''. Uninfested shops are treated as open season for free supplies and equipment.
* ArtisticLicenseAwards: [[spoiler:In the epilogue, Yuuko Sagami earns a Nobel Prize for finding a cure for the infected.]]
* TheAssimilator: Baby Bokors grow into giant humanoid forms after absorbing zombies into their bodies. Getting a taste of someones dna also allows them to take their appearance.
* AssimilationPlot: The goal of the Bokors is to find other Bokor, fuse with them, and then become a larger lifeform with the original Bokor living on as a HiveMind inside it. The first Bokors to do this become the baby Bokor.
* BadAssPacifist: Played with when it comes to the cultists. They believe the zombies are divine, and have developed a special fighting style to deal with them without killing them. However, when it comes to humans who get in their way, they either shoot them on sight or toss them to the horde.
* BadGuysDoTheDirtyWork: At first. Maeda tries to hang back from the action, but eventually is forced to carry his weight in combat.
* BaldOfEvil: The "nimble" creatures.
* BarbieDollAnatomy: The Bokor has no nipples, genitals, or even excretory organs.
* BeautyIsBad: [[spoiler: The beautiful blonde woman's beauty is what tips off the group that the soldiers from the UN are suspicious and of course she turns out to be part of a cult.]]
* BittersweetEnding: [[spoiler: Yuuko Sagami managed to create a cure to the virus and within a few years civilization slowly return to some semblance of normality. Though the infected still remains, in which they are lock away until further cures can be discover. Maeda and Iwakura (who lost his left arm) are working as gardeners at a apple orchard and Yoshioka runs his family-run game center and keeps Yamanoi's broken glasses as a keepsake.]]
* BlobMonster: The Bokor uses a mound made of hundreds of zombies, which can form 'arms' to strike or capture targets. The mound also shift its mass around to protect him.
* CastFullOfPrettyBoys: While the "pretty" part is debatable[[labelnote:*:]]While the main group of four and the juvie warden certainly aren't half bad, pretty much everyone else is either ordinary or sometimes rather ugly[[/labelnote]], the trope mostly comes from the fact that there have so far been two female characters in the entire series so far. Justified in that the main setting is a male juvenile detention center.
* ChekhovsGun: Iwakura's missile launcher, which he used to intimidate one of the Nakazaki brothers from checking up on an [[spoiler:infected Maeda]], was later used by Hitotsukabuto to [[spoiler:shoot down the helicopter piloted by Hatt]].
* ChildSoldiers: Iwakura Gou's backstory revealed that he lived in Africa and his parents were murdered by an anti-government guerrilla group called the "Light Brigade," in which he is forced to [[JoinorDie join them or he will be killed]].
* CoolChair: On top of the mound made of hundreds of zombies, The Bokor sits on a chair made of several zombies kneeling subserviently in the form of a throne.
* CombatClairvoyance: Hitotsukabuto claimed that he can see 2 seconds into the future, allowing him to preemptively react to many dangers. He wasn't exaggerating.
* CompellingVoice: [[spoiler: How the Bokor controls the zombies.]]
* CrapsackWorld: Whether it was before or after [[TheEndOfTheWorldAsWeKnowIt everyone died]] isn't entirely clear.
* {{Cult}}: [[spoiler: The people pretending to be from the UN worship the Bokor as one closest to God and view the zombies as "angels".]]
* DwindlingParty: At the end of each chapter there is a tally on the population of the academy for both inmates and guards. The initial tally was 144 survivors and, as of Chapter 29, now currently has 31 (including the protagonists and along with additional survivors).
* EvenBadMenLoveTheirMamas: Yoshioka leads the boys to his mom's old arcade, which she kept open even after he left home, and sets the high score one last time.
* EliteZombie: Played with. On their base condition, the zombies are your standard fare mindless, slow, shambling undeads, although they're stronger than normal humans. But when a Bokor comes and exerts its influence to control the zombies, they gain massive increase in physical performance, capable of running on par with a car or performing acrobatic flips, enough that even a single one of them is a massive threat.
* EvolutionaryLevels: [[spoiler: The ZombieApocalypse is previous life evolving/dying out so that a new ecosystem in which the Bokor can survive in thrives.]]
* FetusTerrible:
** [[spoiler: After having its head blown off the Bokor grows a babies head in its own head, which proceeds to bite off Maeda's fingers.]]
** [[spoiler:Then we get a male and female bokor who merged together to create a giant fetus which absorbs hundreds of infected to make up its entire body.]]
%% * FleshEatingZombie
* GagPenis: In Chapter 27, poor Maeda suffers the indignity of getting his boxers yanked off by the other boys for a reason that MakesSenseInContext. Their faces register shock and what looks like horror for a second, but the tension is [[MoodWhiplash hilariously deflated]] by the discovery that their mild-mannered friend is seriously ''hung''.
-->'''Yoshioka:''' Jesus Christ, talk about a ''monster''.\\
'''Maeda:''' I ''said'' I'd check it ''myself!''\\
'''Yamanoi:''' Was it that big ''before'' you [[spoiler:got infected]]?\\
'''Iwakura:''' Man, you're packing a ''desert eagle'' down there.
* HealingFactor: [[spoiler: The Bokor can regenerate from having its head cut off or even its brains blown to bits, though it takes time for it to fully regenerate.]]
* HeroicWillpower: [[spoiler: [[AndThenJohnWasAZombie Yamanoi's infected as well, and is rapidly turning.]] In his final moments, he still managed to keep his senses to tell Maeda to shut up and take cover, while he's [[HeroicSacrifice off to light the fire that's going to trigger the big explosion in the tunnel.]]]]
* HiveMind: [[spoiler:Maeda encounters a [[HiveQueen mysterious man]] who can exert some form of sound-based control over the zombies. They pile on top of one another to carry him, and grow in ferocity to defend him.]]
%% * HumanoidAbomination: The Bokor
* ImAHumanitarian: ''Nimble'' zombies were shown doing this after one of their own was killed.
* {{LaserGuidedKarma}}: The surviving and defeated cultists were pay dearly by the inmates. [[ColdBloodedTorture One cultist is seen strung up from a tree and being beaten up like a pinata]].
* MakeMeWannaShout: The Bokor can do this. It's also how they control the zombies.
* MonsterClown: The doglike nimble zombies' facial features - dark-rimmed eyes, missing noses, no lips, and disgusting grins - evoke makeup rather than gore.
* NamedAfterSomebodyFamous: Yoshioka coined Yamanoi's nickname "Noiman" ("no-man") initially as an insult when he was disgusted over the fear-induced reverence that Yamanoi had built upon himself among the inmates. [[InsultBackfire However]], Yamanoi actually liked the nickname as it is an alteration of the name "Neumann", as in [[http://en.wikipedia.org/wiki/John_von_Neumann John von Neumann]].
* OurZombiesAreDifferent:
** Mitsuru theorizes on the fly that [[PlagueZombie a virus is to blame]]. Later evidence of [[ViralTransformation severe mutation]] and an apparent hive mentality could either support or contradict him; the cast may never find out.
** At first the zombies show intelligence even as they try to devour others, but become mindless very quickly. The "nimble" zombies appear to retain their intelligence and even trick the protagonists to entering a shed where they store food. They are also shown ''running away'' from the Bokor. There's also hints that there is still sentience in some normal zombies, shown by them obeying one Bokor over another.
** There's even those that "evolved" into seal-like creatures who get eaten by killer whale like beings.
** Later in the story it is discuss by Yuuko Sagami as to why the infected are different: there are two known types of infected humans that are infected by two types of viruses--F-Virus and M-Virus. The majority of the zombies are infected with the M-Virus, which some people remain in their humanoid forms, while others evolve into other forms, such as dog-like or walrus-like creatures. Humans infected with the F-Virus are more rare, as this strain apparently gives its carrier the ability to heal quickly, and eventually the ability to control M-Virus infected humans.
* ThePenIsMightier: [[spoiler:Yamanoi subdued the Bokor by puncturing his chest with a ballpoint pen and preventing him from using his sound blast and controlling the infected. The end of the pen when it shot out from the Bokor almost ''speared'' Maeda.]]
* PowerUpgradingDeformation: First appearing in Vol. 2, the mutant nimble zombies are roughly canine quadrupeds with human heads, hands, and feet. They completely lose the ability to speak, but run much faster than normal undead.
* ReasonableAuthorityFigure: Arguably, Hitotsukabuto. At first he kicked the main characters out of the Academy as a form of death sentence, but when they returned with the promised weapons, he stuck true to his words of letting them stay (albeit with a little threat). During the Rikkun incident, he was willing to let the main characters go because they ''were'' attacked first. And during the Bokor's attack on the Academy, he protected Maeda from the Bokor's [[MakeMeWannaShout sound blast.]] Later on, he [[spoiler:help the heroes in finishing off the leader of the cultists with a rocket launcher.]]
* ReignOfTerror: Inside the prison, once an inmate with [[{{Yakuza}} serious mob connections]] takes over.
** At first it looked as if Hitotsukabuto was on his way to becoming the [[http://tvtropes.org/pmwiki/pmwiki.php/Film/DayOfTheDead?from=Main.DayOfTheDead Captain Rhodes]] and [[http://tvtropes.org/pmwiki/pmwiki.php/ComicBook/TheWalkingDead The Governor]] of the series. However, in chapter 18 [[spoiler: the GreaterScopeVillain and her private army show up]].
* StalkerWithACrush: Who knows what the deal is when it comes to the Bokor, but it's been obsessed with Maeda ever since he first harmed it [[spoiler: and its got is to infect him and make Maeda into another Bokor.]]
* StoryboardingTheApocalypse: Yamanoi simply explains to the rest of the inmates that humanity is heading for extinction by comparing to how new species begin to appear in rapid succession and alter their environment to suit their needs - which also kill off every other species that existed before them. Namely the new "species" are the Bokor and the infected.
* ThemeNaming: One of the other reasons the [[spoiler: UN soldiers are believed to be suspicious. They all have names of characters from ''WesternAnimation/ThomasTheTankEngine''.]]
* TheTeam:
** TheHeart: Maeda Yoshiaki
** TheLancer: Yoshioka Masafumi
** TheSmartGuy: Yamanoi Mitsuru
** TheBigGuy: Iwakura Gou
** SixthRanger: Hanabata Shinpei
** TagalongKid / TeamPet: Riku
* TooGoodToBeTrue: [[spoiler: The UN soldiers, especially when pretty much everyone who asks them about their loved ones is told that they evacuated safely.]]
* UndyingLoyalty: The main group of four roommates, which later grows to six when they encounter two more survivors, almost always survives primarily because of their fierce loyalty to one another.
* VillainousBreakdown: [[spoiler:Daisy suffered a very literal one after being betrayed by Hatt that her mind regressed to that of a child and believes Hitotsukabuto is her "daddy".]]
* VillainExitStageLeft: Subverted. [[spoiler:Hatt almost had Maeda to gain his Bokor powers, betrayed his expendable followers, and close to escaping on a helicopter until he sees Hitotsukabuto pointing at him with a missile launcher.]]
* VillainousRescue
* YouHaveOutlivedYourUsefulness: [[spoiler:Hatt was truly after the Bokor (namely Maeda) and obtaining its power [[ThereCanBeOnlyOne all for himself]] and used the other cultists as [[UnwittingPawn unwitting pawns]], in which he bashed Daisy with a rock and abandoned her and even killing the helicopter pilot.]]
* ZombieApocalypse: Subverted. [[spoiler:The world eventually got somewhat better after Yuuko Sagami synthesize a cure for TheVirus. However, the infected still remain and the military have them locked away until further cures can be found.]]
* ZombieGait: Regular zombies do this, [[spoiler:but they'll start running if the mysterious man is nearby and in danger. ''Nimble'' zombies are very fast.]]