Okitenemuru is a 2014 sci-fi thriller manga. The manga was published on Manga Action from 2014 to 2018, with a total of 9 volumes.
In modern Japan, a strange event is happening where people's heads suddenly turn into an animal's face, they go feral, and then they explode. Kanata, a young student, is caught up in a strange incident where one of his classmates dies this way and a mysterious government agency comes to quarantine his class, in the process, he learns to enhance his senses by "removing his limiter", making him a unique kind of human called Okitenemuru.
- Advertised Extra: Tokiji. While the official summary paints him as the Deuteragonist of the story, Shiki fits the role much better. Tokiji doesn't actually get that involved with EIID and the investigation, only Kanata is brought into that circle, with Shiki as his bodyguard and the main fighter in that group. And he even gets Put on a Bus when he is turned into a host relatively early in the story, and put in cold sleep to give the EIID time to find and get the antidote from the Singers
- Ambiguously Bi: Ayumi, Shizuku's friend. She is shown to be prone to calling Shizuku her girlfriend in a flashback. She also got the parasite from Saya, which could have been transmitted by sex or kissing, though also by sharing drinks and food. When she is accused, she kisses Kanata, but that could just be the parasite forcing her to kiss him to it can get to him.
- Arc Symbol: Giraffes. There are humans turned into giraffes due to the parasite, giraffes show up when Kanata meets the Singer, it's his favorite animal, and characters being around giraffes was a common motif in the manga covers.
- Arc Words: "The World started without humans, and it will probably end without them too. But either way, we exist."
- Bittersweet Ending: The world is saved, and the singers have given up, but the doctor died in the process. Shiki can't save her sister, who decides to end her own life together with Raven when their son dies. Kanata can no longer have a normal life or see his friends, even though he saved Tokiji, but he seems at peace as an EIID.
- Body Horror: None of the hosts have a good time. Their bodies are mutated, mangled and turned into monstruous versions of themselves. The biggest examples would be Ayumi and Tetsuya. Ayumi sprouts a second, gigantic head with multiple layers of teeth and a hand instead of legs for mobility while her original head becomes melty; Tetsuya is turned into a half-algae monster with a bloated body and head while his limbs became long, all with astrange growth in his body.
- Coitus Interruptus: In chapter 28, a couple is having sex on the balcony before being pushed off of it by a "ghost". It later happens again when investigating that even, where they see two other people being pushed by the "ghost" to have sex before turning into a fused monstrosity.
- Faux Affably Evil: The Section Chief. He acts as a quite lovable manager, if having a bit of a penchant for dirty jokes, he's still quite nice to his underlings and acts politely all the time, but he is a sadistic man that takes pleasure in torturing people and turning them into his food and even poking at the past pains of Shiki.
- My Greatest Failure: Shiki carries the death of her sister, the first okitenemuru, on her neck all the time, and actively describes this as her being the one that killed her. Partly because of this, she is determined to protect Kanata, the second okitenemuru they could find.
- Red Herring: At the beginning, during the school quarantine, the biggest suspect of who among them is infected by the parasite is a man who is revealed to have had sex with the previous host, Saya Inoue. Not only was Saya in a position to be able to infect him, but also, he starts a riot against the EIID, which the members suspect might be the parasite trying to defend itself. It turns out he is fine, the actual infected person is Ayumi, Shizuku's friend.
- Redemption Equals Death: In the final three chapters of the story, the three central villains of the story, Raven, Asu and Satoru, all give up their quest to end humanity. Asu and Raven give up after their child, Enoch, dies protecting Shiki, prompting Asu to realize that destroying humanity will also destroy the things she once sought to protect, Raven simply gives up with his son's death. Satoru realizes that in his question for physical strength, he is still much weaker than the doctor's emotional and psychological strength, prompting him to realize power isn't everything and destroying the giant NEV himself, in the destruction, Asu and Raven decide to stay behind and get buried by the crumbling building together with their son's body.
- Reports of My Death Were Greatly Exaggerated: Asu turns out to have been alive after the helicopter took her down. Kept alive by the Singers, but in a coma until they could get Kanata to wake her up using his powers.
- Sealed Evil in a Can: Invoked by Yakumo. According to him, the only way to defeat an immortal monster is to seal it away. Which is why he made the plan to instead of hunkering himself and the director on the impenetrable bunker, to trap The Swarm in the bunker instead.
- The Sociopath: Sawaki, the man that is behind the drone attacks. He sabotaged his boss' research to save his daughter because he thought it was stealing credit from himself, and went on to become a Serial Killer using the drones by forcing people to have sex and kill themselves in order to steal their pleasure hormones just to pleasure himself with. By the time EIID finds him, he turns the bodies of people in life support into his playthings to attack them and has a plan to force Kanata and Shiki to fuck to death as well. A flashback even shows that he killed a cat with a box-cutter as a kid.
- The Swarm: During an arc, the EIID faces off against a swarm of mosquito-like medical drones that are forcing people to have sex and then kill themselves in order to steal the pleasure hormones from their brains.
- Wham Episode: Chapter 24 "Black Cat Chronicle": Tokiji is turned into a host, slowly turning into a giraffe man.
- Whole Episode Flashback: "Sister in the Dead Line" shows the backstory of Shiki and her sister, the okitenemuru Asu. Asu was in charge of training a group of child soldiers, which she was trying to use to keep them away from actual combat. One day, they fled and tried to fight on their own, but they were used as lure by the EIID itself, and killed together with the enemy when EIID sent an airstrike, leaving Asu and Shiki as the only survivors. Asu snapped, after her powers allowed her to absorb the emotions of the dead children and went on a rampage, killing whatever she could find, friend or foe, and needed to be taken out by an helicopter, as Shiki watched.