History Anime / DecaDence

* CityInABottle: Deca-dence.

* DrivenToSuicide: [[spoiler:Since his teammate was killed, Kaburagi has been gradually starving himself to death. His discovery of Natsume's status as a bug in the system breaks him out of it, since he finds new purpose in helping her survive.]]

* ArcWords: "We exist for the sake of the system." and "The world must be rid of bugs." [[spoiler:Both are said by Hugin, the mysterious administrator that oversees the smooth operation of Deca-dence, and thus the all-powerful AI they serve alongside making sure that Kaburagi continues to do his job as a "bug hunter".]]

The series, directed by Yuzuru Tachikawa (''Manga/MobPsycho100'') and produced by Studio NUT, was released during the Summer 2020 Anime Season

* AllAmazonsWantHercules: As shown in the aftermath of the underground raid in EP 4, Kurenai is positively ''delighted'' at the prospect that Kaburagi is returning to active duty alongside her. Dialog from the rest of her squad implies she's been holding this torch for years and it hasn't flickered since then.

* AmazingTechnicolorPopulation: Some Gears have green, blue, or purple skin color. [[spoiler:This is because they're essentially RPG avatars and one episode even has Natsume see a "Skin Shop" though she doesn't understand what it actually is. Their true forms also come in a wide variety of colors.]]

* ArmCannon: Post-upgrade, Natsume's mechanical hand now has five fingers and can transform into a harpoon launcher.
* ArtificialLimbs: Natsume lost her right arm when she was young. It was replaced with a prosthetic that only has three fingers and much less finesse and control than a normal hand. Kaburagi later remodels it to have a full five fingers for improved dexterity while allowing the prosthesis to [[ArmCannon double as a needle launcher]].

* AuthorityEqualsAsskicking: Kurenai is the leader of Tankers who fight alongside the Gears and one of the strongest as well. Natsume looks up to her as her idol.

* TheCynic: Kaburagi doesn't have a very bright outlook on the world and thinks Natsume shouldn't have many hopes to improve the world.

* DarkSkinnedBlonde: Kurenai has tanned skin and blonde hair.

* DisappearedDad: Natsume's father died when she was younger during a Gadoll attack that ended up costing her her arm.

* MyGreatestFailure: For Kaburagi, telling Mikey how to [[spoiler:release his avatar's limits and leading to him getting disassembled.]]

* ReallySevenHundredYearsOld: Kaburagi looks to be in his 40's or 50's but [[spoiler:his human appearance is just an avatar, the real cyborg is at least over a hundred years old.]]
* RetiredBadass: Kaburagi is a forcibly retired Ranker. His skills have yet to dull even after all the years, however, and he's perfectly capable of training Natsume and defending her from any threats beyond her capabilities.
* SavvyGuyEnergeticGirl: The dynamic between Kaburagi and Natsume.

* ArcWords: "We exist for the sake of the system." and "The world must be rid of bugs." [[spoiler:Both are said by the mysterious administrator that oversees the smooth operation of Deca-dence, the game, and thus the all-powerful AI they serve alongside making sure that Kaburagi continues to do his job as a "bug hunter".]]

* HopelessBossFight: The [[spoiler:blizzard-generating gadoll at the top of Mt. Everest is this, as part of the admin's plans for a heroic comeback of retired top players.]]

* ArtificialLimbs: Natsume lost her right arm when she was young. It was replaced with a prosthetic that only has three fingers. Kaburagi later remodels it to have a full five fingers for improved dexterity while allowing the prosthesis to [[SwissArmyAppendage double as a needle launcher]].

* SwissArmyAppendage: Post-upgrade, Natsume's mechanical hand now has five fingers and can transform into a harpoon launcher.

* AmazingTechnicolorPopulation: Some Gears have green, blue or purple skin color. [[spoiler:This is because they're essentially RPG avatars and one episode even has Natsume see a "Skin Shop" though she doesn't understand what it actually is. Their true forms also come in a wide variety of colors.]]

* AttackItsWeakPoint: Aside from ''extreme'' blunt force trauma, Gadoll regenerate damage so quickly the only way to kill them is to hit them in major arteries with special harpoons meant to bleed them dry. Due to the "Zone" gravitational fields they emit as a defense mechanism, this can only be done at close range.

* {{Kaiju}}: The gigalind of the first episode looks like a land whale with the shell of a sea snail that's nearly as big as the whole Deca-Dence.

* AmazingTechnicolorPopulation: Some Gears have green, blue or purple skin color. [[spoiler:This is because they're essentially RPG avatars. Their true forms also come in a wide variety of colors.]]
* AnimalisticAbomination: The Gadolls come in a wide variety of forms and sizes, looking like insects, crustaceans, mollusks and reptiles of a huge size that have [[AlienBlood green blood]].

* FirstEpisodeTwist: The final scene of the first episode has [[spoiler: [[TrumanShowPlot small technicolor robots viewing the the main characters]]. Episode 2 goes on to reveal that after the apocalypse, full body cyborgs had taken control of the planet and turned it into a hybrid wildlife preserve and {{MMORPG}}. All the soldiers we've seen are remotely-controlled avatars, and humans are none-the-wiser {{NPC}}s with tracking/control chips lodged inside them. Kaburagi turns out to be one of these cyborgs, whose discovery that Natsume is a "bug" in the system lacking one of these chips piques his interest and gives him a new lease on life.]]
* ImpossiblyCoolWeapon: The entire fortress can transform into a cannon.
* {{Kaiju}}: The gigalind of the first episode looks like land whale with the shell of a sea snail that's nearly as big as the whole Deca-Dence.

* MyGreatestFailure: For Kaburagi, telling Mikey how to [[spoiler:release his avatar's limits.]]
* RetiredBadass: Kaburagi is a forcibly retired Ranker.

* ArtShift: [[spoiler: The aliens that control the Gears are far more cartoonish than the humans of the setting.]]

* FirstEpisodeTwist: The final scene of the first episode has [[spoiler: [[TrumanShowPlot small technicolor aliens viewing the the main characters]]. Episode 2 goes on to reveal that after the apocalypse, aliens had taken control of the planet and turned it into a hybrid wildlife preserve and {{MMORPG}}. All the soldiers we've seen are remotely-controlled avatars, and humans are none-the-wiser {{NPC}}s with tracking/control chips lodged inside them. Kaburagi turns out to be one of these aliens, whose discovery that Natsume is a "bug" in the system lacking one of these chips piques his interest and gives him a new lease on life.]]

* MegaCorp: The Solid Quake corporation, which [[spoiler:controls Deca-dence and appears to own at least a portion of a potentially alien species' population.]]

* WhamEpisode: Episode 2: [[spoiler:The Deca-dence fortress, as well as the entire continent of Eurasia, is really something between a wildlife sanctuary for humans and a real-life video game setting for a seemingly alien race.]]

* ArtificialLimbs: Natsume lost her right arm when she was young. It was replaced with a prosthetic that only has three fingers.

* YouGottaHaveBlueHair: Linmei has purple hair while Fennel has green hair.

* DrivenToSuicide: [[spoiler:Since his team was killed, Kaburagi has been gradually starving himself to death. His discovery of Natsume's status as a bug in the system breaks him out of it, since he finds new purpose in helping her survive.]]

* CharacterCustomization: There is at least shop in the Gears' section of the fortress that offers this.

* AmazingTechnicolorPopulation: Some Gears have green, blue or purple skin color. The reason behind it hasn't been explained yet.
* AnimalisticAbomination: The Gadolls come in a huge variety of forms and sizes, looking like insects, crustaceans, mollusks and reptiles of a huge size that have [[AlienBlood green blood]].
* ArtificialLimbs: Natsume lost her right arm when she was young and was replaced with a prosthetic that only has three fingers.
* BareYourMidriff: Some females, like Linmei, are seen with shirts that expose their navels.

* AmazingTechnicolorPopulation: Some Gears have green, blue or purple skin color. This hasn't been explained yet.