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''Region'' is a {{horror}} {{manga}} by Fujisawa Yuki, the author of ''Manga/{{BioMeat|Nectar}}''. It began its run in 2007, and was serialized in the magazine Play Comic.

Something strange is going on in Tokyo. Despite it being February, it hasn't snowed once this year, and insects are dying off at an alarming rate. While politicians and scientists debate about the effects of global warming, the populace remains completely oblivious to and unprepared for what is coming next.

Chief Togakushi, a widowed engineer who works for a regional power company, is called upon to inspect a newly installed wind farm that is about to go into operation. Along with his lovestruck coworker Asagiri and a guide from the prefecture government, Togakushi notices that none of the equipment on site is receiving power from the basement generators. When the group heads below to investigate, they are stunned by what they find: the basement is teeming with hundreds of thousands of starving rats who have been chewing through the electrical cables. And, as their unfortunate guide soon learns the hard way, the swarm is quick to turn its attention to the new source of food that has just stumbled upon it.

As Togakushi and Asagiri rush to find a way to contact headquarters after discovering that their cell phones are mysteriously not working, the widower's panicked thoughts turn to his high school aged daughter, Kanon, and bug-obsessed younger son, Ryuuto, when he looks into the horizon and realized that there are no lights coming from the direction of Tokyo.

His fears are well founded, as the swarm he encountered is nothing compared to the ravenous plague of rats that is descending on the city. As the Togakushi family rush to find each other before night falls and they are left with no place to hide, scattered emergency radio reports indicate that the entire country of Japan may be under siege.
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!! Tropes present in ''Region'' include:

* AllMenArePerverts: Any male besides Togakushi, Kizaki and any other main character will be hit with this trope mercilessly. This includes the surviving men that were sent to exterminate the infestation.
* BeetleManiac: Ryuuto, who is willing to risk bullying from his classmates and elementary school teacher over his refusal to let them kill the insect collection they were keeping as a class project. This leads to him sleeping with the insects in his bed to help them stay warm, much to his unsuspecting sister's chagrin.
* DyingMomentOfAwesome: [[spoiler: Kizaki and Hayase running/wading through a very sea of hungry, flesh-eating ants to carry Kanon and Ryuuto to safety, then going ''back'' to get them a boat, and only showing minimal signs of pain as they're being eaten. Considering how everyone reacted to being eaten prior, this is quite a feat.]]
* EatenAlive: The fate of the swarm's victims.
* FeatheredFiend: Completely averted. When it looks like Kanon and Ryuuto, trapped on the roof of their house, appear ready to be devoured by the surrounding swarm, a flock of crows descend from the sky and devour the rats, inadvertently saving their lives in the process.
* {{Gonk}}: Just like in ''Manga/{{BioMeat|Nectar}}'', lots and lots of unsympathetic secondary characters look like they were beaten with the fugly stick nine times over.
* GreenAesop: Again like in ''Bio Meat'', the source of the problems (the massive insect die-off and the rat population explosion, who no longer have insects as a viable food source) is humans screwing up the environment. Unlike the previous manga, however, this is something you could almost imagine happening in real life, seriously amping up the creep factor.
* HalfTheManHeUsedToBe: When Kanon's ankle is grabbed by a man who is pleading for help, she is horrified that everything below the man's waist is covered with rats, happily gorging themselves on what little remains of his flesh.
* HeroicSacrifice: [[spoiler: Kizaki and Hayase carry Kanon and Ryuuto to the ocean to save them from ants, then ''go back'' to grab a small boat for them to use, knowing that the ants will overcome and devour them.]]
** GoOutWithASmile
* {{Humans Are Bastards}}: Used interchangeable with the manga's {{Green Aesop}}. Best example comes when one of the group of survivors huddling in the elementary school for refuge beats a pest control worker with a chair in a rage and panic when he reminds the other survivors that the invading rats will double their numbers until they overrun the area and endanger the human population. The rest of the survivors (barring the heroes) cheer the attacker on.
* InfantImmortality: Ahaha, yeah right.
* {{Kids Are Cruel}} Ryuuto's classmates, in addition to being ridiculously {{Gonk}}, {{Kick The Dog}} when they crush one of his cherished Hercules beetles. Why? Because they got annoyed when Ryuuto proclaimed their right to live and responsibility to their care against them wanting to get rid of them because they thought they were useless.
* ParentWithNewParamour: While Chief Togakushi [[ObliviousToLove seems oblivious to the feelings of Asagiri]], Kanon is quick to notice the way she acts around him. This drives a wedge between the father and daughter, as she feels that it's too soon for him to abandon the memory of her mother.
* SwarmOfRats: Taken UpToEleven.
** Now with ant and mosquito swarms.