History VisualNovel / OneKagayakuKisetsuE

** Kohei's aunt and guardian, Yukiko, never makes any direct appearances, but she does help out during Akane's route and interacts with Kohei in Mio's route.

** Kohei's aunt and guardian, Yukiko, never makes any direct appearances, but she does help out during Akane's route.

* TheGhost: Kohei's aunt and guardian, Yukiko, never makes any direct appearances, but she does help out during Akane's route.

* GayOption: Subverted, though at times Hikami may seem like, he really just thinks of Kohei as a close friend. Though he does (as a joke) say that if Kohei wanted to try it with him, he wouldn't object.

* ButtMonkey:
** Nagamori by Kohei.
** Sumii to less extent.
* [[CantHoldHisLiquor Can't Hold Her Liquor]]: Mio Passes out relatively quickly when drinking during Akane's route, justified as she is a petite and underdeveloped 10th grader.
* CatchPhrase: Nagamori says "You know" and "after all" a lot, leading Kohei at one point to call her ''Nagamori of the planet 'You know after all'.''
* CaughtTheHeartOnHisSleeve: Mio tends to hang on Kohei's sleeve, [[spoiler: becomes a small plot point later on in her route.]]
* CerebusRetcon: Misaki [[spoiler: decides to take her revenge on Kohei for running into her by saying "Who are you?" when he walks up to the roof, little did she know that he was in the middle of a breakdown because he actually '''was''' being forgotten by everyone, and she was the last one that would remember him.]]
* CrashIntoHello:
** How Kohei first meets Nanase, not so much MeetCute as Meet Cruel. Also happens with Nanase regularly.
* CuteMute: Mio.
* DarkAndTroubledPast: Kohei. [[spoiler:It becomes a major plot point late in the game.]]
* DidIJustSayThatOutLoud: Kohei speaking his mind by accident during Nanase's h-scene.
--> Kohei *thinking to himself*: (We look like we are connected at the hips..)
--> Kohei: "We look like we are connected at the hips." *Kick*
--> Nanase: Stop it, you're embarrassing me!
--> Kohei: (Did I really just say that out loud?)
* DeadpanSnarker: Kohei from the beginning right to the end.
* DefrostingIceQueen: Nanase starts this way but melts herself. Kohei is too [[TooDumbToLive dense]] to notice.
* DeusSexMachina: To return from the eternal world, Kohei must have sex with a consenting girl to form a bond with them that can be used to return after a year. Subverted in some routes wherein you can choose to have a non-sexual, but nonetheless romantic relationship.

* EmotionlessGirl: Akane, getting a small smile out her really feels satisfying.

* {{Expy}}: {{Inverted|Trope}}. Ayu, from ''VisualNovel/{{Kanon}}'', is an expy of Nagamori.
* FaceDoodling: After Mio passes out from drinking too much, Shiiko draws on her face, she wakes up later on and leaves without noticing.
* FeaturelessProtagonist: Taken a bit too literally with Kohei. Even during scenes when he's kissing someone, he has no eyes, nose, etc. depending on the scene.

* TheGlomp: Mio does this to Kohei quite a bit. One time she jumps him in the dark and he attacks her, believing she's a mugger.
* HeavySleeper: Kohei every morning in the beginning.
* JerkWithAHeartOfGold: Kohei starts a jerk, finds the gold later.
* {{Mythology Gag}}: If you look in the shopping district in ''ONE'', you can see a sign that says rorikon (as in lolicon). Key would go on to make Kanon, which also has a "lolicon" shop in the shopping district.
* {{Tsundere}}: Nanase is a Type B, in this case the trigger is just Kohei being present in the room, [[JerkAss though its not difficult to understand why..]]
* InnerMonologue: Kohei does this in the game.

* LateForSchool: Kohei and Nagamori have to sprint to class regularely to avoid being late because of Kohei's antics when getting up. Nagamori and Kohei running to school is also the first CG the player sees in-game.

* MomentKiller: A combination of situations 3 & 4 occurs during Nanase's H-Scene, Nanase is too nervous to go through with it, so just when it seems they are about to start, she clicks on the television and blurts out "OH LOOK SUMO WRESTLING IS ON, I LOVE SUMO WRESTLING." Kohei just sighs and tries to steer thing back on course.
* NearRapeExperience: Kohei plans to have Nagamori raped by an anonymous person but decides that this is a bad idea. This is the good route.
* NeverGetsDrunk: Akane can hold her alcohol like a pro, even though she isn't even old enough to be drinking. She goes even farther by not passing out, remaining completely level-headed, and even cleaning the entire house.
* NewTransferStudent: Nanase turns out to be one, and Shiina also transfers schools if you take her route.
* NotAMorningPerson: Kohei, who needs to be woken up by Nagamori at the start and (depending on the route) an alarm clock, Nanase or trains himself to do it.

* ObliviousToLove: Kohei during Nanase's route, he can't understand why she is disappointed when he takes her to cheap Ramen restaurant to try this new ramen on Christmas eve. He does eventually get it when she runs out crying.

* PatientChildhoodLoveInterest: Nagamori, '''extremely''' patient.

* ReflectionlessUselessEyes: Misaki.
* RetGone: Kohei's ultimate fate in the bad endings.

* TransferStudentUniforms: Nanase wears her old school uniform even though she got one from the school, she just likes her old one. [[spoiler:This comes in handy for Mayu's route when they need a spare uniform for her]].

* VagueAge: Shiina never has her age stated. [[TokenMiniMoe However, we know that she is younger than high school age]] (likely to be either thirteen or fourteen as it was one year before she graduated from middle school).

* VisibleSilence: Mio, all the time, justified considering she is mute.
* WhamEpisode: [[spoiler:Late in the game, Kohei ends up remembering the full extent of his DarkandTroubledPast, and the deal he made to erase himself from the real world in order to live in a blissful eternity. The plot takes a sharp turn towards DarkerAndEdgier and TearJerker territory from here on out, with Kohei realizing that he has a very limited time left in the real world, and the rest of the cast beginning to forget about him. In the bad endings, he's unable to stop or mitigate this turn of events, and ends up disappearing from the real world entirely.]]%%Invoked
* YamatoNadeshiko: Nanase dreams of becoming a true "maiden", so she tries to behave kind and cute, however, her act goes down thanks to Kohei's tricks.

* BlindIdiotTranslation: The English translation of the remake is overall very passable, but still has some amusing gaffes such as one of Kohei's professors being referred to as a "she" when clearly having a male voice and Kohei's classmate Minami[[note]]"South" in Japanese[[/note]] being named properly when Kohei is speaking to him but named as "South" when he's the one speaking.

''ONE'' tells the story of Kouhei Orihara, a Japanese high school student who suddenly finds his ordinary, everyday life pushed to the brink of collapse by the seemingly inexplorable expansion of an inner reality which threatens to replace his own. In the long and cold winter before the [[TheNamesake Radiant Season]], he will encounter new friends, rediscover old promises, witness ties forged and broken, and learn of the things which everyone must leave behind.

Kouhei suspects that at some point his current life will change while living a peaceful daily routine. His parents died when he was very young, and after his younger sister dies, he begins to seclude himself in the Eternal World, a world within his mind. The game's recurring theme is a focus on the Eternal World, an alternate space that Kouhei created out of his want for a place in which nothing ever changes. He starts receding into this world about a week before disappearing, during which every one (including the girl he loves) forgets about him, and he falls into the Eternal World completely, making it seem as if he never existed in the real world. His only hope of returning is to form a strong bond with someone prior to leaving, and to follow his guide back to the real world.

** Nagamori by Kouhei.

* CatchPhrase: Nagamori says "You know" and "after all" a lot, leading Kouhei at one point to call her ''Nagamori of the planet 'You know after all'.''
* CaughtTheHeartOnHisSleeve: Mio tends to hang on Kouhei's sleeve, [[spoiler: becomes a small plot point later on in her route.]]
* CerebusRetcon: Misaki [[spoiler: decides to take her revenge on Kouhei for running into her by saying "Who are you?" when he walks up to the roof, little did she know that he was in the middle of a breakdown because he actually '''was''' being forgotten by everyone, and she was the last one that would remember him.]]

** How Kouhei first meets Nanase, not so much MeetCute as Meet Cruel. Also happens with Nanase regularly.

* DarkAndTroubledPast: Kouhei. [[spoiler:It becomes a major plot point late in the game.]]
* DidIJustSayThatOutLoud: Kouhei speaking his mind by accident during Nanase's h-scene.
--> Kouhei *thinking to himself*: (We look like we are connected at the hips..)
--> Kouhei: "We look like we are connected at the hips." *Kick*

--> Kouhei: (Did I really just say that out loud?)
* DeadpanSnarker: Kouhei from the beginning right to the end.
* DefrostingIceQueen: Nanase starts this way but melts herself. Kouhei is too [[TooDumbToLive dense]] to notice.
* DeusSexMachina: To return from the eternal world, Kouhei must have sex with a consenting girl to form a bond with them that can be used to return after a year. Subverted in some routes wherein you can choose to have a non-sexual, but nonetheless romantic relationship.

* EasyAmnesia: As you near the end of the game, [[spoiler:everyone who once knew Kouhei slowly starts forgetting him until only the girl you chose remembers him (or alternatively, no one, if you didn't manage to get on a route) at which point he disappears]].

* FeaturelessProtagonist: Taken a bit too literally with Kouhei. Even during scenes when he's kissing someone, he has no eyes, nose, etc. depending on the scene.

** [[spoiler:After Kouhei disappears, but the game is told from the chosen girl's point of view until he comes back a year later.]]

* GayOption: Subverted, though at times Hikami may seem like, he really just thinks of Kouhei as a close friend. Though he does (as a joke) say that if Kouhei wanted to try it with him, he wouldn't object.

* TheGlomp: Mio does this to Kouhei quite a bit. One time she jumps him in the dark and he attacks her, believing she's a mugger.
* HeavySleeper: Kouhei every morning in the beginning.
* JerkWithAHeartOfGold: Kouhei starts a jerk, finds the gold later.

* {{Tsundere}}: Nanase is a Type B, in this case the trigger is just Kouhei being present in the room, [[JerkAss though its not difficult to understand why..]]
* InnerMonologue: Kouhei does this in the game.
* LaserGuidedAmnesia: Toward the end, [[spoiler: everyone forgets only Kouhei; no other memories are lost, the ones involving Kouhei are appended to exclude him]].
** This also happened [[spoiler: to the friend Akane was waiting for and Hikami (where only Kouhei remembers him)]].
* LateForSchool: Kouhei and Nagamori have to sprint to class regularely to avoid being late because of Kouhei's antics when getting up. Nagamori and Kouhei running to school is also the first CG the player sees in-game.

* MomentKiller: A combination of situations 3 & 4 occurs during Nanase's H-Scene, Nanase is too nervous to go through with it, so just when it seems they are about to start, she clicks on the television and blurts out "OH LOOK SUMO WRESTLING IS ON, I LOVE SUMO WRESTLING." Kouhei just sighs and tries to steer thing back on course.
* NearRapeExperience: Kouhei plans to have Nagamori raped by an anonymous person but decides that this is a bad idea. This is the good route

* NotAMorningPerson: Kouhei, who needs to be woken up by Nagamori at the start and (depending on the route) an alarm clock, Nanase or trains himself to do it.

* ObliviousToLove: Kouhei during Nanase's route, he can't understand why she is disappointed when he takes her to cheap Ramen restaurant to try this new ramen on Christmas eve. He does eventually get it when she runs out crying.

** Kouhei's aunt takes care of him even though she is rarely home.
** Kouhei also says he feels like a parent during Shiina's route.

** [[spoiler:Mio and Kouhei]] have one of these as kids.
** [[spoiler:Nagamori and Kouhei also have one near the end of her route.]]

* RetGone: Kouhei's ultimate fate in the bad endings.

* SpiritualSuccessor: ''[=ONE2=]: Eien no Yakusoku'' explains more about the Eternal World but isn't made by Tactics, has different characters, setting, etc. (It also is not translated)

* TrademarkFavoriteFood: Akane's waffles, Kouhei's spicy ramen, Misaki's curry and Shiina's hamburgers.
* TransferStudentUniforms: Nanase wears her old school uniform even though she got one from the school, she just likes her old one.

* WhamEpisode: [[spoiler:Late in the game, Kouhei ends up remembering the full extent of his DarkandTroubledPast, and the deal he made to erase himself from the real world in order to live in a blissful eternity. The plot takes a sharp turn towards DarkerAndEdgier and TearJerker territory from here on out, with Kouhei realizing that he has a very limited time left in the real world, and the rest of the cast beginning to forget about him. In the bad endings, he's unable to stop or mitigate this turn of events, and ends up disappearing from the real world entirely.]]
* YamatoNadeshiko: Nanase dreams of becoming a true "maiden", so she tries to behave kind and cute, however, her act goes down thanks to Kouhei's tricks.