Let the carnage begin!
Chika Amagi used to be an Ordinary High-School Student, until she awakens after having killed five people who tried to rape her. Transferred to the mysterious Haguro Island prison, Chika discovers she's not the only young woman afflicted with the Medusa syndrome that turns women into ruthless killers. Now Chika must survive a world full of killers and depraved individuals and a mysterious N.G.O. Superpower.
A thriller, action, horror, mystery and drama manga by Yoshinobu Yamada, who also authored Cage of Eden and Deathtopia.
The work contains Tropes of:
- All Men Are Perverts: Whenever they're not serial rapists or just depraved individuals, men tend to be simply perving on women.
- All Women Are Lustful: Just because most men are perverts, it doesn't mean the girls can't be the same. Karen and Katya are easily the most lustful of the original nine Medusas.
- Alternate Identity Amnesia: At first the girls were unaware of what their Murder model was doing, until Kasumi decides to not delete their memories and let them know exactly what they are and what they did.
- Anti-Hero Team: Of the Nominal Hero variety, since while the Medusas are all dangerous serial killers, they at least target even worse people and eventually start becoming Fire-Forged Friends.
- Attempted Rape: Chika is almost gang raped for a Snuff Film on the very first chapter, which is why she snapped and killed them. Getting almost raped happens on every story arc.
- Asshole Victim: Many of the people the Medusas kill are awful human beings and scum of the worst kind.
- Ass Shove:
- Chika kills Tomomi Mizuno by making him fall into a pole anus first from a height of 4 stories until it comes out of his mouth. Jeesh.
- When she's being held captive by Yuuri Nezu/Jeffrey Dahmer, it turns out Katya stuffed a small gun in her pussy and a knife on her ass.
- Bald of Evil: Tomomi Mizuno of Tendougumi is completely bald and he's a ruthless and depraved Yakuza with an obsession with asses.
- Battle Ballgown: In their second Satanophany experiment, Chika and Sachiko both wear bridal dresses as part of the killing game.
- Brainwashed: Medusa syndrome is supposedly some new mental illness that turns seemingly innocent girls into serial killers. In actuality, a MegaCorp discovered a combination of drugs and VR that effectively allows them hack a woman's mirror neurons and implant a Split Personality of their own design. Due to a mixture of wanting Super Soldiers and their Mad Scientists having a murder fetish, all of the personalities are modeled after Serial Killers. So long as the victim has not yet killed their first human, the conditioning will fade away over time, but after that, it becomes irreversible.
- Brawn Hilda: Kyoko Kanzaki is a former pro-wrestler and a tower of muscle with a short haircut and two noticeable scars on her face.
- The Cameo: On the first issue Shirou Mariya of Cage of Eden is briefly seen among Chika's classmates.
- Carnival of Killers: In a different take on this trope, the Medusas are all killers used as either hitmen or guinea pigs in the plans of a nebulous MegaCorp.
- Cartesian Karma: Even if the family of Medusa murder victims are told the truth, they couldn't care less about the masterminds and have no desire to take Revenge on them. As far as they are concerned, the blame lies with the Medusas alone.
- Cast Full of Crazy: Just for starters, the main characters have all been implanted with the personalities of infamous serial killers and sociopaths. And that's without including the perverted warden, the amoral lead scientist and the necrophiliac guard.
- Corporate Conspiracy: Officially speaking, Medusa Syndrome is a mysterious new mental illness that strikes seemingly ordinary young women and turns them into Serial Killers. These murderers are then brought to specialized private prisons in order to treat them. In truth, a MegaCorp figured out some combination of drugs and VR that can effectively hack a person's mirror neurons to implant a new personality into them. So far, the "treatment" doesn't work on most people, but women are more vulnerable to it due to having more mirror neurons. The MegaCorp provides the treatment to a very large number of women under false pretenses and then uses a Frame-Up on the ones that show a reaction to use them as test subjects. The government is curiously unconcerned as to why so many prisoners die and why the prisoners only get worse.
- Crippling Castration: A rapist with a Gag Penis gets his dick shot off by Maki right before she blows his face off.
- Katya bangs a Yakuza with an equally large dick, right before she cuts it off and leaves him to bleed out. She proceeds to do the same with all of his companions.
- Cruel and Unusual Death: Dying in Satanophany it's usually not a pleasant affair, either by Medusas or by their enemies.
- Depraved Bisexual:
- Floyd King is a Scary Black Man who if he can't get his rape itch satisfied by a nearby woman, he'll rape a man instead.
- Tomomi Mizuno is a Yakuza with an obsession with asses, and he'll rape anyone, be they male or female, if he likes their ass.
- Even Evil Has Standards: Kanzaki might be a brutal enforcer and fighter, but even she finds Mizuno's disturbing obsession with asses to be distasteful.
- Fan Disservice: There's a lot of nudity and panty shots, but they're usually accompanied by attempted rape, brutal fights and gory deaths.
- For the Evulz: While there are a few pragmatic motives, like Mad Science and creating Super Soldiers, a lot of the bad guys do what they do just because the idea of brainwashing innocent girls into Medusa Serial Killers gives them a sexual thrill.
- Gender-Restricted Ability: The "treatment" used to convert people into Medusas and implant a Split Personality is easier to perform on women than men due to them having more mirror neurons.
- Heel–Face Door-Slam: Kazunari Sakagami after being repeatedly and violently raped by Floyd King, realizes what a horrible person he's been for raping multiple girls and decides to, somehow, atone for his crimes. Sayoko doesn't care about his so called atonement and kills him without mercy.
- Hotter and Sexier: Than both Cage of Eden and Deathtopia, having some borderline-H sex scenes and even more graphic death scenes.
- Hour of Power: The drugs that trigger the Medusa transformation only lasts for a few hours. Chika becomes able to activate it when under stress is a sign her strength is growing.
- The Immodest Orgasm: On chapter 109 Chika and Sayoko proceed to have loud and passionate sex after their Relationship Upgrade while Kirika loudly masturbates while thinking of Niina in the next room. This only confuses and annoys Miina who's on the other room.
- Love at First Sight: Yuuji Tani of Tendougumi claims to have fallen in love with Youko Kuroki on first sight. That his feelings were genuine truly saddens her and she mourns him after she kills him.
- Men Are the Expendable Gender: During the SS Sanctuary Arc of all the 35 members of Tendougumi aboard the ship, only the two women; Kyoko Kanzaki and Yan Bongfa survive. Niina Rudou also survives unharmed, but he had already defected to Kiriko's side and he's a Wholesome Crossdresser who decides to live as a woman.
- Mistreatment-Induced Betrayal: Jin Mizuno/Niina Rudou turns on his father Tomomi in favor of Kiriko, since he was tired of being anally raped by his father.
- Mythology Gag: Miina Isurugi can't help but notice the similarities between her and Niina Rudou, which fits since in Cage of Eden, the former was the body double of the latter. Even Niina's real sex inverts the one she had with Miina.
- Neck Snap: Medusas are strong enough to snap the neck of another human with surprising ease, either using their hands or their Murderous Thighs.
- No Name Given: The Female Doctor's actual name wasn't revealed until chapter 118, Kasumi Makube.
- Only Sane by Comparison: Katya Rastorgueva occasionally plays the straight man to the wackier killers that she associates with, usually Karen. She's still a serial killing Psycho Knife Nut and sex maniac.
- Only Sane Man: Michitaka Amagi and Nishi the prison guard are easily the most sane and moral people on the cast and the first ones to notice how fucked up everything is.
- Out with a Bang: Karen and Katya both dispose of two killers while they were in the middle of banging each other. In fact, they do this on two separate occasions.
- Panty Fighter: The girls fight and kill in outfits that do a terrible job at covering their panties when they use kicks.
- Parental Incest:
- Niina was constantly raped by his father Mizuno, which is why he turns on him at the first opportunity.
- Mamoru Ishiguro tells Miina right before he tries to rape her that he always desired to rape his own daughter.
- Katya admits she was raped by her father when she was younger.
- Reused Character Design: Satanophany reuses the design and even names of characters from the author's previous works.
- Chika Amagi is clearly based on Yui Kisaragi from Deathtopia, who was in turn based on an older Rion Akagami from Cage of Eden. The main difference between the first two is that she lacks Kisaragi's cowlick.
- Michitaka Amagi is based on an older Koh Fujimura, who was in turn based on an older Akira Sengoku. The main difference is that he needs glasses while Fujimura no longer needed them.
- Aya Tomoe is practically an older Aya Tokiwa, having the same headband, hairstyle and even tendency of wearing bloomers underneath her skirt for easy mobility.
- Karen Kirishima is downright transferred from Deathtopia, including her love of removing the eyeballs of her victims.
- Miina Isurugi is simply older than how she looked in Cage of Eden with the exception she's really female and not a cross dressing boy.
- Seri Doujima is a dead ringer for Saki Segawa, having the same pink hair and eyes.
- Serial Killer: The Medusas are young women who have all committed some serious murders, either willingly or due to their Split Personality, and the body count just gets higher whenever they go against other killers.
- Split-Personality Merge: At first the Medusas were unaware of what their murderous personalities did, but once Kasumi decides to not erase their memories, their serial killer and normal personalities start to become a combination of both.
- Theme Serial Killer: Since the Medusas were all given the mindset of different serial killers, their skills and preferred style of killing is based on that killer's preferences.
- Chika is a Jack of All Trades since her murder model, Henry Lee Lucas, didn't have a preference for any sort of weapon.
- Sayoko Onigahara is a Master Poisoner due to her model being certified Mad Doctor and Nazi war criminal, Josef Mengele.
- Miina prefers using traps and strangulation, plus her Villainous Harlequin outfit are all reference to infamous Monster Clown John Wayne Gacy.
- Karen Kirishima has as model the notorious sadomasochist Albert Fisher, known as the Moon-Maniac. As such she's a Combat Sadomasochist who uses a whip.
- Seri and Maki Doujima are based on the killer brothers Gary and Thaddeus Lewington, as such they're the best gunslingers among the Medusas.
- Katya's murder model is Andrei Chikatilo, The Butcher of Rostov; the Red Ripper. As such she's a very skilled Psycho Knife Nut dressed in mink.
- Kiriko Murasaki is a deadly Boxing Battler due to her model, Albert DeSalvo, Boston Strangler, also being a former boxing champion.
- Those Wacky Nazis: Sachiko's murder model is infamous Nazi Mad Doctor Josef Mengele, the 'Angel of Death'. She even dresses like a military officer while in Medusa mode.
- We Hardly Knew Ye: Shion Magaki is introduced alongside the other inmates, only to die shortly after the second experiment, with the one who did it not being clarified.
- Wholesome Crossdresser: Niina Rudou is a boy cross dressing as a girl, and he's the only member of Tendougumi who defects, mostly due to falling in love with Kiriko and taking her virginity.
- World of Action Girls: While there are many male combatants, Medusas are almost always female and they're quite deadly.
