Yuki Nagato

Yuki Nagato (長門 有希) is a fictional character in the Haruhi Suzumiya franchise. She is initially portrayed as an introverted, taciturn bibliophile. She is actually an artificial human created by the Data Integration Thought Entity, and possesses supernatural powers as a result. She never officially joins Haruhi Suzumiya's SOS Brigade, but observes and takes part in club activities on the behalf of the Entity while still being the only member of the Literary Club. In addition, she is present to ensure that Haruhi does not use her godlike powers, and aids the other Brigade members in stopping forces that cause her to do so. The alternate Yuki established in the fourth light novel, The Disappearance of Haruhi Suzumiya, is the main character of the spin-off manga The Vanishing of Nagato Yuki chan.

Appearance
Apparently, Yuki has extremely pale skin, as there are numerous times in the original light novels where Kyon describes her face, neck, hands, or fingers (as she flips the pages of the book she is reading) as "white". Also, Kyon always comments on Yuki's uncanny ability to walk "soundlessly" (this can be seen in the anime when Yuki is exploring a public library with Kyon who appears puzzled by it). Yuki is attractive enough to earn an "A-" grade from Taniguchi and, as Taniguchi states, has a lot of secret admirers. In The Disappearance of Haruhi Suzumiya, when Kyon came face to face with Yuki in a twilight realm (here she is simply a normal, shy girl) blushing in front of him, he was stunned by her and even felt for a moment that it would be good to stay in this realm and join the Literature Club for good. She initially wears glasses, but forgets to regenerate them after they are broken whilst she is protecting Kyon from Ryoko. When she realizes she no longer has them, Kyon tells her she looks cuter without them, prompting her to leave them unregenerated.

Background
Yuki Nagato is a quiet high school freshman that is the only member of the SOS Brigade that willingly joined Haruhi's SOS Brigade and was not "voluntarily arrested," or forced into joining, by Haruhi Suzumiya. She was a member of the Literary Club, whose other members were all seniors who graduated, leaving Yuki the sole member of the club. She lives alone in the same apartment complex as Ryoko Asakura, in room 708. She wears her school uniform almost all the time (even on non-school days). She initially wears glasses but, after the confrontation with Ryoko Asakura, they broke. She planned to create new ones, but decided against it after Kyon told her that she looked cuter without them. She wears a different outfit for the first time when the SOS Brigade goes on vacation to the remote island in "Remote Island Syndrome".

Yuki is a "humanoid interface", or artificial human, created by the Data Integration Thought Entity, a god-like alien figure, for the purposes of interacting with and observing events on Earth. She was created 3 years ago and, though possessing the exterior of a high schooler, she is in fact about 1,319 years old, when one takes into account the time she has spent outside of Haruhi's universe. Specifically, she has been created to observe Haruhi, who can create huge quantities of data from nothing. Haruhi represents a potential route to autonomous evolution, an ability that the Overmind does not have and one which could help accelerate the evolutionary standstill the Overmind has reached.

As an artificial human, she has numerous paranormal abilities. She is capable of manipulating the properties of the environment and any materials within it at any scale to her desire, referred to as "bogus magic" by Kyon. For instance, she can modify the "elemental boost information" of a baseball bat to hit only home runs, nullify data links (removing other artificial interface connections from their bodies), plus she is able to make a cover-up story (since Ryoko was gone, she made a cover up story that she moved to Canada), and reconstruct a classroom, down to the last detail, after everything in it was completely destroyed. As a result, she is capable of feats of superhuman strength, agility, and stamina. In one instance, she was unfazed while impaled by multiple metal spikes, and effortlessly reconstructed her body afterwards. Her state also affords her an extreme level of intelligence. She can comprehend the rules and concepts of a game instantaneously, as well as create flawless strategies based on her observations, and was able to learn how to play a guitar mere moments after picking one up. However, she has been seen to be fallible, such as when she reconstructed the devastated classroom but forgot to reconstruct her broken glasses. Yuki also has a lack of understanding towards social norms and earth technology, as demonstrated by her bluntly literal future predictions and her clumsy attempts at using a computer mouse. However, it can be construed that the mouse incident came from her watching Kyon hold the mouse away from Mikuru. This is likely due to her self-imposed state of near-total isolation in order to interfere with as little of the environment around Haruhi as possible.

Personality
Yuki has a very stoic and introverted personality, preferring simple body language rather than speaking. When prompted to speak, she does so in a very concise manner, always speaking in a monotone and displaying a dispassionate expression. She thinks very rationally, and finds it difficult to communicate with normal humans due to her intelligence and lack of empathy. She very rarely, if at all, talks directly to Haruhi. She enjoys reading, and is seen reading a book in the majority of her appearances, typically of the science fiction or mystery genres. As the series continues, she displays an enjoyment of computer games and develops a sense of humor, although her unchanging facial expressions make it near-impossible to discern whether she is joking or not. Despite her reserved manner, she is reliable and trustworthy, resulting in Kyon trusting her more than any other member of the SOS Brigade. Though seemingly cold and devoid of emotions at first glance, Yuki subtly shows a genuinely warm care and concern for her fellow SOS Brigade members, Kyon in particular.

This is shown by her keeping Kyon warm with her cardigan as he fell asleep in the club room, and her taking care of Mikuru when the latter fainted from terror in the "Murder Island" incident. At the end of The Disappearance of Haruhi Suzumiya, she also expresses gratitude towards Kyon's promise to protect her from being deleted with a simple "thank you" (even though up this point, expressing gratitude or emotion is supposedly uncharacteristic of her). In The Disturbance of Haruhi Suzumiya, where a guy named Nakagawa supposedly fell in love with her, she revealed to have felt a slight sense of disappointment when in the end, it turned out to be a misunderstanding involving the Data Overmind. Also, when Kyon and Haruhi are trapped in closed space in The Melancholy of Haruhi Suzumiya, Yuki was able to communicate with Kyon via the computer in the club room and tells him that "It's our desire that you return. Haruhi Suzumiya is a valued subject." but also that "I [Yuki], as an individual, also feel a desire for you [Kyon] to return."

In the alternate world depicted in The Disappearance of Haruhi Suzumiya, she is depicted as a very shy girl, a polar opposite of her normal self. This Yuki is friends with Ryoko Asakura and is hinted to have feelings towards Kyon. This character is built upon in the spin-off manga, The Vanishing of Nagato Yuki-chan.

SOS Brigade role
Yuki is described by Haruhi as the SOS Brigade's "indispensable silent character." She was neither recruited by nor did she join the Brigade but was actually included along with the room when Haruhi arrived and declared it as her own. Whenever she is in the club room, she is usually reading. Similar to Itsuki Koizumi, Yuki is obedient when orders are given; however, her loyalties lie more with Kyon rather than Haruhi. The other members often rely on Yuki and her abilities whenever needed most, notably when the SOS Brigade was losing in the baseball tournament, the contest against the Computer Society, and in the case of the camo cricket. Aside from this role, she is also protective of Kyon, as evident when she used her body to shield him from an attack by Ryoko Asakura.

In the SOS Brigade's amateur movie production The Adventures of Mikuru Asahina, Yuki was cast as the leading antagonist. She was portrayed as an evil alien, who could also use magic.

Kyon also realized after the "camo cricket" incident that Yuki plays a "behind the scenes" role, making her one of the puppeteers whose goals are to ensure Haruhi is fully satisfied and that order and balance are maintained. Her intentions of being in the Brigade are to monitor Haruhi and prevent her from feeling bored or greatly disappointed because it is generally believed by the Data Overmind that a drastic event that could end the universe would occur. It is also believed that Haruhi is also the key to autoevolution and to stopping the evolutionary stand still they have come to, thus it is important for Yuki and other humanoid interfaces to continue their observations. As part of her observation duties she has the ability to detect any spatial changes in the environment caused by Haruhi and will act to prevent them from persisting. An example of this is during the unscripted attack in the first fight scene of the Brigade movie, when she tackled Mikuru in order to remove her contact lens which had temporarily caused the fictional "Mikuru Beam" to become real. She later bites her to inject nanomachines that disrupt any powers Haruhi gives her.

Able to alter reality to some extent (though not even approaching the ability of Haruhi), Yuki was revealed to have been responsible for the world Kyon found himself in, where Ryoko, Yuki, Mikuru, Itsuki, and Haruhi were all normal beings (meaning Itsuki's "Agency", Mikuru's time traveling organization, and the Data Overmind were non-existent) and the latter two never went to North High, thus no SOS Brigade, due to internal errors revealed to be something she was not supposed to have: emotions. However, she had left Kyon's memories intact, as well as provided an escape program, should he desire to return to the old world. Despite the fact that Yuki was most likely going to be deleted for her actions, Kyon has had her remind the Data Overmind that if that were to happen, then Kyon could always make Haruhi realize her powers (by telling her about John Smith) and make her alter reality so that Yuki would exist while the Data Overmind didn't, knowing that the Overmind cannot lay a finger on Yuki. If this happened, it would ruin reality thus making their mission a failure. The Yuki from the alternate world stars in the spin-off manga, The Vanishing of Nagato Yuki-chan.

Voice actresses
In the Japanese anime as well as in the radio dramas, the role of Yuki is played by Minori Chihara. Her English counterpart is portrayed by Michelle Ruff. Minori Chihara would reprise her role as Yuki in an episode of Lucky Star, as did Ruff. Moreover, Minori Chihara would go on to voice Minami Iwasaki, who has a similar personality to Yuki, in Lucky Star; Ruff also followed in the same path, portraying the English voice for Minami and Tsukasa. Minori Chihara also sings the opening theme to Ga-Rei Zero, "Paradise Lost", which Yuki sings in an episode of the Haruhi spin-off series, The Melancholy of Haruhi-chan Suzumiya.