Yuki's parents became Humanoid Interfaces when Haruhi changed the universe.Because erasing someone from existence is equal to murder, and Haruhi would never do such a thing.
Originally, it was Nagato who was the "back-up" while Asakura was the original Agent assigned to observe Haruhi.Hence her having the emotions and actually in a position to observe Haruhi, while Nagato was in stand-by in the Book Club Room. But Haruhi, being Haruhi, chose Nagato. The Integrated Data Entity switched Nagato's and Asakura's roles, something Asakura and her Sponsor didn't accept. This is only borderline WMG as it's fairly well supported.
Nagato must obey Kyon's every commandIn the episode with the missing computer club guy, Nagato freezes halfway through pointing at something when Kyon says "Hold it." I cannot remember if it is the case in the anime but in the book it is explicitly stated that she stays perfectly still despite the oncoming giant insect until Kyon says "you can move again." If you combine this with the fact that only Kyon's orders could make her open the door in the island mystery one I think this conclusion seems fairly reasonable.
Alter-Ryoko was Yuki's subconscious desire to stay human.No form of Yuki would want to hurt Kyon, but the fact that Alter-Ryoko knew Kyon was trying to change things back when even Human Yuki didn't suggests she was created differently from everyone else in the Alternate Universe. Some small part in the back of Yuki's mind gave herself a companion in the new world that would defend it. Add a dallop of guilt for original Ryoko's erasure, mix in Ryoko's normal psychopathy, and stir.
Nagato could hijack Haruhi powers because Kyon transfered them to herNagato was able to use Haruhi powers to alter reality in Vol.4 only because Kyon - probably subconsciously - transfered Haruhi power, or allowed them to be transfered. Tachibana Kyoko thinks that Kyon can transfer Haruhi power to Sasaki - or at least is crucial in doing so. Some dialogs in Asahina Mikuru's Adventure suggest that Kyon is somehow 'key' to Haruhi power. Of all people in the world, who Kyon trust most and wouldn't mind if they were holders of supernatural powers? Nagato.
Kyon is unconsciously a genie, and grants the wishes of those closest to himSeveral of the above WMGs relate to this, but this is different in an important way: Kyon grants wishes, but not his own. At least not directly. Nagato, a sci-fi bookworm wanted to know everything and be an alien. So she's turned into an Integrated Thought Sentient Entity interface, which knows pretty much everything AND is an alien. Koizumi is classy, and given his bootlicking personality he wants to be high up in some organization. So, he's given the most important job an esper can have, and Haruhi considers him her second in command. Asahina's motives are unclear. (And this troper personally believes the WMG that she's only helpless to get close to Haruhi and Kyon) Since she's very secretive, I suppose her wish would be that she gets to be "in the loop". Notice that she also refuses to tell people things that she knows they already know. Either that or she wants to know her current problems will get better in the future, which she knows becuase she has seen her future self. Lastly Haruhi, who just wants to be special. If Kyon really does care about Haruhi, then he's made her the most important person in the world, with more than three organizations all wanting to know more about her, yet all subservient to her wishes. Now Kyon never gets his wishes unless someone else helps him out. The only problem is that other people that are somewhat close to him don't get any abilities, or else Taniguchi would be the most popular guy in school. It also seems that Kyon's sister doesn't have any wishes. On the other hand, Kyon's sister gets a magical cat in the books and is allowed on the island in the anime. Another problem is that Ryoko Asakura got a wish granted, and she definitely doesn't seem to be a special person of Kyon's, unless Nagato wished to save Kyon.
Yuki doesn't really want to be normal.Kyon thought he did, but realized he was wrong when he actually had the choice. Alternate-universe Yuki didn't have the chance to properly consider it, since she didn't know what her alien self had done to change things. For all we know, she would have come to the same realization as Kyon. (I don't expect this guess to be popular, since it makes her much less The Woobie.)
Yuki is the real/original reality bender.It's clear that Yuki has the most power out of the three helpers, and she apparently steals Haruhi's powers once. As a sci-fi aficionado, she always wanted to be an alien, and the Integrated Data Sentient Entity isn't very stock as aliens go, it's quite well thought out. She probably lost control of her powers once before, so she buried her emotion with her powers. It's possible the relationship with her Nakama is her way of making sure it doesn't happen again, so that she can restore her own emotions. Asakura was shocked with her coding ability, - which is apparently above normal - to save Kyon, and of course, it was very dramatic. It may also be possible when Haruhi was destroying the world that it was Yuki's jealousy, since Haruhi doesn't go anywhere near as out of control when she's jealous of Yuki. Yuki constantly bails out Kyon of situations she creates because she wants to be useful. As for Asahina, she was probably created to give Kyon something to look at without objectifying herself. Itsuki was brought in because of his tendency to speculate and help Kyon figure things out, or to divert things. Haruhi's presence could be a result of any number of things:
Yuki is going to die in the tenth book.Then, Haruhi will finally find out about the web of secrets around her. And then she shall bring down divine fury on the people who dared harm a Brigade Member. There are plenty of ways that she could find out, but the one I'd like the most: immediately after Yuki passes on, Kyon turns to Haruhi, plays his trump card, explains the situation, and sits back to watch the fireworks.
Haruhi subconciously allowed Yuki to steal her powerIt makes things more interesting, interesting enough for a movie. Thats why Kyon's trump card works-Haruhi will let her powers be used for things which are arguably 'fun', but removing one of her brigade members? No dice.
Haruhi is really Jesus' second human incarnationShe's testing if humanity is yet ready to go back to Eden now. By accepting someone as weird as the melancholical and bossy Haruhi, they would prove theirselfs to be worthy.
Yuki has thousands of masks and yukata hidden in a closet in her apartment.It's possible that, since she remembers every summer in Endless Eight, that Yuki also kept all of the yukata Haruhi bought her and all of the masks Yuki bought herself. And, since each mask and yukata appear to be different, the time duplicate destruction is avoided.
Yuki does in fact have emotions, but only Kyon can see them.I have not read the novels, but Yuki expresses emotion three times that I know of: happiness during the Day of Sagitarius, anger during the Ryouko fight, and boredom during Endless Eight. Mikuru and Itsuki know she's an alien so they don't bother to look for signs of emotion, and Haruhi is, of course, completely oblivious.
Nagato broke her directive of "observation" and hooked up with Kyon during one or more iterations of Endless Eight.The "errors" accumulating due to uptime far longer than her original design specification, along with frustration at her powerlessness to end the endless summer, drive Nagato to act out by sleeping with Kyon. Kyon does not remember, but is aware of something "changed" in Yuki, while Yuki cannot forget, but also cannot do anything about her newfound feelings, as Haruhi's jealousy would cause The End of the World as We Know It. As a result, she creates an Alternate Reality where Haruhi is out of the picture, she can be a normal human free of the burden of her duty and memories, and she and Kyon can get to know each other and fall in love. The one memory she leaves herself of her old life is also the moment when she first became attracted to Kyon out of more than just intellectual curiosity (though she did not realize it until later): the episode at the library earlier that year. Additionally, Nagato does not truly give Kyon an option out of I Want My Beloved to Be Happy; rather, she is thwarted only by the foresight of her earlier, coldly logical self, who does not understand the feelings that she will come to experience later on. This only adds to the angst that runs beneath her Emotionless Girl exterior.
Yuki was the one responsible for Endless EightIt was a last ditch attempt to prevent Disappearance from happening.
Haruhi subconsciously "remembers" Nagato taking her power, and recreated "The Vanishment of Nagato Yuki Chan" world for her AU self.
Yuki didn't steal Haruhi's powersI never really bought the whole stealing powers thing to begin with. It was left too vague and I think if she'd had that ability she'd have used it during the Endless Eight. Nevertheless I accepted it because we had nothing else to go on, until book nine. It showed the powers were transferable and the implication seemed to be that the powers currently reside in whoever Kyon wants to be with on a subconscious level. First it was Sasaki then Haruhi. The point at which Yuki "obtains" the powers is Disappearance, which also happens to be the point at which the narrative (written by Kyon) starts focusing on Yuki instead of Haruhi, coincidence? I reckon that this is the point at which Kyon shifts affections to Yuki and Yuki suddenly finds herself in possession of the powers. Being an alien she actually realises she's got them, unlike the previous two owners, and uses them. The question is, does she still have them?
Yuki gave Haruhi her powers three years ago on behalf of the IDE.The IDE always had such reality warping powers and simply couldn't think of a way to use them to improve itself anymore. They decided to give someone else their abilities and see what they would do with them. So they picked a race they were interested in, humans, and then narrowed down the choice to Haruhi because A. she wants weird things, B. she's secretly rational and won't notice and threaten them and C. She's a decent person deep down and won't do anything too dangerous. Yuki could steal her powers because she gave them to Haruhi in the first place. It's why she was around three years ago. It's also why her abilities can involve reality warping as well, such as changing the baseball bat to always hit home runs. When she went on a rampage after stealing said powers, the IDE didn't punish her not because Kyon threatened them, but because they would lose Kyon's support and influence over Haruhi and therefore an external factor introducing major changes. She finally started doing weird stuff, after all. Finally, perhaps Haruhi isn't the only one with weird reality warping powers and this is all a giant experiment the IDE is carrying out. They grant these powers and take them away again if they're not learning anything from the wild chaotic humans, like Sasaki's insistence on normality.
Yuki was programmed to have an emotional bugThe IDE is a super intelligent entity with access to near unlimited computing power. It would not make an error of that magnitude in such an important program. The error was programmed in intentionally by either the IDE or Yuki herself as Xanatos Roulette of currently unknown purpose. Alternatively the emotional bug was the result of Yuki, tired of serving the IDE after the Endless Eight loop, was able to escape its control. They engaged in a data war similar to the one in Snow Mountain Syndrome, and the result was the alternate reality Kyon found himself in. The winner depended on whether Kyon succeeded at reversing the effect, although who actually won when he succeeded is unknown.
One or more characters is a Time Lord.... is this just here to fulfill the 14th Example Law?
Yuki ordered Ryoko to attack Kyon.To be trusted by Kyon, Yuki told Asakura to atack Kyon so that Yuki could save him. If Asakura really was trying to kill someone, im pretty sure that there are better ways that trying to kill him with a knife. And this can be match with the "Kyon is god". Think about it, Asakura was trying to kill Kyon to watch what Haruhi do, but if Kyon REALLY is God, she attacks him to see what God can do. This would explain why she chose the Knife Nut option, to get the maximum emotional response. Yuki kept to her plan though.
The events of "Disappearance" are directly due to Yuki developing romantic feelings for Kyon.The way her new, "normal" world was set up made things quite easy for her in that regard:
In the 10th Novel, Yuki will catch Asakura's knife with her bare hand right as she trys to kill Kyon.'Alpha' Yuki that is, sliding into the 'Beta' timeline with 'Alpha' Kyon. Because she's already done it twice, why not a 3rd time?
Yuki did not leave Kyon with his memories intact because She Wants Her Beloved To Be HappyShe did it because she knew that he was the only one capable of choosing the "strange" real world over the "normal" false one. Yuki does not exist in time and space the exact same way as we do. Because of the "synchronization" of her past and future selves she, like Dr. Manhatten, experiences her entire existence simultaneously. She knows exactly what she's going to do but is powerless to stop it, it will happen, because it must happen, because it has happened. Mikuru and Itsuki by admission and evidenced by their actions would prefer quiet ordinary lives, and Haruhi cannot carry it out because she is clueless to the situation (and might not even notice the change in the first place) and not focused enough to figure it out before the deadline anyway. Not only is Kyon the only one capable of choosing the old world knowing full well the responsibilities that come with it (having already done it once before in Melancholy), he's also the only one capable of taking the action necessary to see it through to the end, to the point of mobilizing the future versions of the himself and the SOS brigade to come back and save his own life when he's injured. He was not given a choice, he never had a choice because there was never any doubt which course he would take. He was given a job to do and he performed it. The moment he finds the bookmark there is absolutely no doubt about what will happen. Hell, in the movie version at least she comes right out and tells him this is why he was left with his memories intact, because he was the only one who could and would stop her.
Nagato drugged the tea she gave Kyon the first time (storywise anyway) she invited him to her house.All the weird backdrops are Kyon tripping the hell out.
Kyonís mission to find the keys in the Disappearance arc was meant to be a lot harder.Kyon learned which school Haruhi went from Taniguchi. Taniguchi is supposed to be absent like other former East Middle school students. Yuki didnít consider the fact that Taniguchiís father would force him to go to school with a high fever. Kyon is supposed to find Haruhi by himself.
Yuki is aware that the Five-Man Band will destroy the world.She does the minimal possible in Disappearance to move all the members away from each other and is thwarted when the IDSE overrides her common sense to impose the "interesting" event that will doom the world. Mikuru is from the end of the world and has been sent back to mix things up in random ways (making her seem rather stupid) in a vain attempt to save the Earth from the coming doom.
Yuki Nagato is human.Yuki was born to a Mr. and Mrs. Nagato and was attending North High until Haruhu jacked Kyon into the first data explosion. At that point the IDSE infected Yuki and froze her in place to await Haruhi's entry into that school. When Yuki blocked out data manipulation she didn't become human, she just became uninfected. Thus Ryoko's comment about Yuki's puppet master, etc.
Yuki didn't steal the power, she moved it.The resolution at the end of The Disappearance was not complete because some of the power remained with Sasaki. Note how the anti-SOS pops up shortly afterwords and in a very immature condition, from which they rapidly evolve to be a match for the SOS brigade.
The series will end exactly like the first Star Trek movie.Yuki and Haruhi merge.
Miss "Gate Length" is the result of Moore's Law gone wild.Hence her family name. See: gate length defined.
708 is just as meaningful as 505.Now, has this already happened, or will it happen?
Human Yuki is not powerless.
Yuki is the only person out of the three supernatural SOS members telling Kyon the complete truth.Her organization are only observing for the time being, and as of yet don't see any reason not to tell Kyon the information he asks for - even moreso now they know that Kyon can easily give them a hard time if he needs to. Yuki only warned him about her perhaps lying to him incase her superiors ever change their mind.
Yuki shot first!
Yuki is a tool left by Neglectful PrecursorsHow can a life form not evolve? The answer is that Yuki's patron is NOT a living being. It did not evolve over time. It was created in its current form by others some time ago. Yuki is a Berserker. She has forgotten her role in eliminating the previous civilization and is now looking for some goodlife on Eatth.
Yuki is using Kyon's brain.
Alt-Yuki was lying about not being a writer.The files she deleted from her PC were the fanfics she had written about her being a Mary Sue alien engaged in fun adventures with the boy from the library. (Once he walked into her clubroom, these were no longer needed.)
Yuki wasn't given the ability to express emotions normally because she is the humanoid interface in charge of observing HaruhiHaruhi is human so to properly understand her actions requires the ability to understand human emotions, so the interface in charge would need to have emotions to properly understand the thought process behind them. Yuki is the only humanoid interface with normal human emotions but she can't express them because normal human interaction would interfere with her objective. the other interfaces were not given actual emotions because they didn't need them but were given the ability to fake a normal human personality in order to be able to gather information in ways that Yuki would be unable to without being given the ability to express emotions.