She is voiced by Minori Chihara in the Japanese version of the anime and by Michelle Ruff in the English version, the former of whom also voices Miku Izayoi.
Yuki is very short for her "age" compared to the rest of her friends. She has short jagged purplish hair which never grows and golden brown eyes. She used to wear glasses but stopped after Kyon told her she looked better without them.
Nagato rarely wears anything beyond her school uniform unless instructed to, even on weekends, though she's been known to wear more casual clothes during vacations (eg Remote Island Syndrome, Endless Eight).
When Kyon met Nagato in year -3, she looked exactly the same as "now", except for some qualities of facial expression. This was in marked contrast to Haruhi Suzumiya, who looked the expected three years younger.
Yuki Nagato is a humanoid interface with the appearance of an ordinary North High student. It is not clear which faction of the Integrated Data Sentient Entity she serves, though she has confirmed that she belongs to the "majority" faction and is not a member of a radical one.
Nagato was created with limited social abilities, something she claims will affect her until she ceases functioning. She rarely speaks, often ignoring attempts to communicate (in Editor in Chief★Straight Ahead!, Itsuki Koizumi feared she would ignore a demand from the Student Council President to visit and so delivered the message himself), using gestures like nods, staring or pointing, or giving one word replies. Sometimes she provides a complex explanation using mostly scientific terms to explain even the simplest of things, or announces events which other Brigade members might not notice. Her responsiveness has increased over time, at least when dealing with those she is familiar with. For instance, she ignored Tsuruya's attempts to communicate with her in year 0, but recited poetry with Tsuruya when prompted in The Astonishment.
Nagato's voice is usually a monotone. Nagato's facial expressions rarely change, and any such changes are minor. Careful observation is required to discern any emotional responses; Kyon is not necessarily correct in his observations. He believes the expressions of her face have changed since their first meeting (from her perspective) in Bamboo Leaf Rhapsody.
As a result, Nagato frequently acts "shy". For instance, she appeared unable to obtain a library card without Kyon's help. When interacting with people outside of the SOS Brigade, she frequently stares at the floor and either gives very short responses or says nothing at all, even if angry. For instance, when asked questions by Tsuruya, she first said nothing, but later responded; she reacted the same way in Live A Live when asked Haruhi's location by schoolmates. Her silent trait extends to interactions with members of the SOS Brigade; when Haruhi Suzumiya wanted to throw out her books from the SOS Brigade headquarters, Nagato could do little more than glare at her. Nagato has frequently communicated with Koizumi, but only on paranormal or scientific matters. Even when communicating to Mikuru Asahina about a mission in the prologue to The Intrigues, Kyon did most of the talking, and Nagato contributed "footnotes" when explaining something that Kyon forgot or could not understand. Nagato has become increasingly more willing to communicate with the S.O.S Brigade, especially Kyon and Asahina.
This is a trait not shared by some other Integrated Data Entity humanoid interfaces. Ryouko Asakura has showed a wide range of social abilities, even taking part in events not related to her mission. However, she still appeared to have a limited vocal range and set of facial expressions.
Nagato has shown a poor understanding of emotions, especially her own. She attributed her actions in The Disappearance of Haruhi Suzumiya to "erroneous files accumulated in her memory database". When pushed to describe her own emotions, she usually says nothing or gives an understated answer, such as "relatively" enjoying books and being "a little" disappointed at being rejected. She rarely expresses opinions, and these are usually based on those of the Integrated Data Sentient Entity (such as describing a data organism as "primitive", describing human computers in a similar manner, or commenting positively on interactions with the Sky Canopy Domain despite the negative effect on her). She was able to determine why "Michuru" thought her behavior was disturbing when Michiru stayed over at her apartment overnight, also commenting that Michiru's analysis was wrong. Nagato has made repeated attempts to relieve Kyon's concerns. She often tells him "don't worry" when she is injured or something strange panics him and can tell if someone is disturbed. She also behaves in a manner which would please Haruhi (such as telling her that her cooking was "delicious" or setting up a mystery in Mystérique Sign). However, her analyses of human behavior are often flawed, being based on incomplete information.
Nagato seems to have little interest in generic human activities and only participates in events dictated by Haruhi Suzumiya. She steps out of this to protect the timeline or to prevent the creation of closed space (she participated much more forcefully in baseball once closed space was created, upon Itsuki Koizumi's prompting). This behavior extended to her method of decorating her apartment (she didn't before The Disappearance) and her lack of desire to engage in Literature Club activities, at least in her first year at North High. (In her second year, her attempts at recruiting students involved her describing deficiencies in verbal communication.) Nagato is very fond of reading and later developed computer programming as a hobby. She has occasionally demonstrated interest in human activities, such as watching fireworks and reciting poetry.
Nagato appears to have a low opinion of herself. She was willing to endure prolonged isolation for her mission when watching over Kyon and Mikuru Asahina for three years in Bamboo Leaf Rhapsody and made no effort to break free from the time loop of Endless Eight, as her purpose was only to observe. In The Dissociation she stated that she would protect the rest of the SOS Brigade, but Kyon said "having no concern for yourself is behavior I absolutely will not allow."
Nagato poorly conceals her inhuman nature although her normal appearance helps her avoid suspicion. For instance, when referring to someone by name, she always uses their full name. (When speaking to someone, she does not use their name, simply referring to them as "you". She referred to the Computer Society President as a "male student", despite having heard his name from Emiri Kimidori. Other humanoid interfaces have not demonstrated this behavior.) Kyon even noted that she doesn't blink often (in The Sigh) or simply stares into space.
According to Ryouko Asakura, Nagato taught her to act according to her own will, which she believed had something to do with evolution, and that she and Nagato are more alike than Kimidori.
Yuki Nagato has special powers being a humanoid interface.
Nagato has displayed superhuman strength, agility, and stamina. She appears to be immune to pain.
Nagato has displayed unusual minor abilities, such as holding her breath for a very long time, not suffering sunburn despite her very pale skin, and being immune to the effects of alcohol. She also appears to be immune to human diseases, so any time she does get ill, it's seen as a serious attack on her.
Nagato's reaction time is fast enough for her to repeatedly block several laser beams from Mikuru's "Mikuru Beam" attack.
Nagato seems to have "odd" food requirements. Sometimes she eats at normal speed (such as during The Sigh of Haruhi Suzumiya), but later she often ate at rapid speed (seen in Lone Island Syndrome). Kyon became so used to this he became worried when Nagato ate slowly in Snow Mountain Syndrome. In The Intrigues she ate a triple-sized portion of food during a regular meal. She often ignores food or drink placed in front of her, but at other times has gulped down large offerings of food.
Nagato has very keen eyesight, and her glasses seem to have been props, since she stopped wearing them after Kyon complimented her on how she looked without glasses. She has demonstrated the ability to discern body temperature, detect directions, sense laser beams and subatomic particles and even determine their mass. She can sense other data organisms and all manners of strange phenomena, but the ability is not infallible. (For instance, she could not immediately determine that a pair of dogs had been infected with a data parasite, and took time to determine that Nakagawa was an esper.) Nagato could "scan" a highly-advanced computer which contained information about time travel.
As shown in Live Alive, Nagato seems to be able to memorize the piece of music by looking at it once. In the same episode she is also able to play the guitar without any problems. As shown in Endless Eight, Yuki Nagato has the ability to remember things that are supposed to be erased by being a part of the Integrated Data Sentient Entity. However, she is not infallible; she once forgot to reconstruct her glasses after they were broken in a battle. Nagato could "intuit" data she had collected from a damaged advanced computer.
In the anime, she seemingly has difficulties with some distinctly human objects, such as computer mice and rifles.
She demonstrated difficulty in drawing pictures of faces in Snow Mountain Syndrome.
Nagato's multitasking abilities gave her a great advantage when playing Sagittarius III. She was able to control 20 groups while countering a hack attempt simultaneously.
As a humanoid interface, Nagato has numerous powers, seemingly enhanced when in a space under data jurisdiction. Many but not all of her powers require her to use "incantations" (in which she speaks a computer language very quickly) or arm movements (best seen in The Disappearance). In the first light novel, this speech was translated as Structured Query Language (SQL):
ORDER BY aggressive_combat_data
By contrast, in the anime, her incantations sound like she is speaking backwards quickly.
Nagato can manipulate "chance", such as determining who takes the "long straw", as demonstrated most clearly in The Intrigues.
Nagato can manipulate the properties of the environment, such as when she modified a baseball bat to only hit home runs, modified a baseball's movements, or destroyed a section of fence. Kyon refers to this as "bogus magic". She can modify some of her own properties (such as her weight/mass, which Kyon noticed when taking her and Haruhi on a bike ride).
Nagato appears to have the ability to teleport, which she demonstrated in the The Melancholy of Haruhi Suzumiya when breaking into space under data jurisdiction. However, she seemingly could not enter Haruhi's sealed space. She used a similar ability in the running contest in The Sigh of Haruhi Suzumiya. The way she described her ability to Kyon made it seem like teleportation, but she still performed worse than Haruhi Suzumiya in the contest. She later used a similar ability to escape an irate person (while the rest of the Brigade had to run) and may have used the ability when blocking the Mikuru Beam. In Mystérique Sign she used a similar ability to enter a data organism's dimension, which bore similarities both to closed space and data jurisdiction.
Nagato can use her abilities to reconstruct her body (healing from damage). This appears to be an active process, and she has not used the ability while using other data abilities (she put her repair request in queue). Nagato once healed Mikuru from a knockout poison and was able to at least partially heal a wounded Kyon, making it look like he had fallen down the stairs.
Nagato can directly communicate with computers and Kyon's cell phone, even when the latter was trapped in sealed space. She has only rarely demonstrated this ability and has only been seen using it to communicate with Kyon. She was able to program Mikuru's TPDD through touch.
Nagato has demonstrated the ability to create a "cover story" with her data manipulation abilities.
Nagato can create a barrier which renders people invisible and inaudible. Nagato had to dissolve the barrier to take action.
She may be able to alter computers with her abilities, having created a "do-it-yourself" computer for the Computer Research Society using an operating system that made no sense to the Computer Research members, and could use her "magic touch" to fix software bugs.
She can communicate with the Integrated Data Entity in order to gain information and permission to use otherwise forbidden techniques (such as nullifying Asakura's data link). Sometimes the entity will not give her the information she seeks, however (such as when she tried to get answers to Kyon's questions about life after death).
Nagato was able to transfer some of her autonomous judgment capabilities to Emiri Kimidori when she fell ill in The Astonishment of Haruhi Suzumiya.
She can modify human memories, an ability she revealed in The Disappearance, when she told Kyon that if he'd known what she was going to do, she would have removed his memories.
In Bamboo Leaf Rhapsody, Nagato "froze" Kyon and Mikuru outside of time for three years, explaining that this ability could only be used in an emergency. She later stated (in The Disappearance) that she could not leave them unattended while they were in this state. She also confirmed that she could not initiate time travel.
Nagato used "dissolution factors" as an attack form to "dissolve" Asakura. The first time, they were fighting in data jurisdiction space, the second time she erased Asakura in The Intrigues.
Nagato can apparently initiate some form of "magic attack" outside of data jurisdiction. In The Sigh of Haruhi Suzumiya, Haruhi ordered Nagato to attack Mikuru with magic, full blast, and Nagato hesitated, unsure if she should follow the command. (She elected not to.)
Nagato can alter the weather, revealed in The Boredom of Haruhi Suzumiya when Kyon asked her to make it rain. She was reluctant to do so, however, as that would alter the weather patterns for a long time thereafter. (Kyon decided not to ask her to do so.)
Nagato also has the ability to "steal" some of Haruhi's powers and use them to her advantage, something she did in the Disappearance arc as a result of "errors". Her powers altered the previous 365 days and created a massive timequake.
Data Jurisdiction Powers
Nagato's powers appear to be expanded while within data jurisdiction. Nagato once entered another interface's data jurisdiction space, repairing it from the damage, and another time she used an "incantation" to enter similar space created by a more primitive data organism, which bore some similarity to both data jurisdiction and sealed space. (That space was automatically repaired when the organism was defeated.) In a data jurisdiction space, she was able to create "icicles" from the surrounding structure and use them to attack an enemy. She could use this ability in "reverse" to counter Ryoko Asakura's similar attacks.
In the anime version of Mystérique Sign, Nagato demonstrated the ability to create a repulsion field which damaged (but did not destroy) a primitive data lifeform, in a space created by that organism.
Nagato has shown the ability to manipulate data links, enabling her to destroy or manipulate data-based organisms.
She has demonstrated the ability to reconstruct areas under data jurisdiction which had been damaged.
In The Sigh of Haruhi Suzumiya, Nagato injected nanomachines into Mikuru via bite to prevent her from using the Mikuru Beam. In The Disappearance, she also injected Kyon with a stealth operation screen and a protective field to protect him from hazardous effects of time travel. In each case, the bite marks swiftly faded.
In The Disappearance, Nagato was able to transform her glasses into an injection system, which she referred to as "compounding". When Kyon complained, she transformed it into a device resembling a "science fiction" needle gun. PrecognitionEdit Nagato has displayed at least limited precognition. She had at least some foreknowledge of Ryoko Asakura's attack and Kyon being trapped in sealed space in The Melancholy of Haruhi Suzumiya (saying that Kyon would be "first" if the radical faction moved and telling him to "be careful" before he was trapped). In the anime version of Live Alive she gave a long series of seemingly accurate (but mundane) predictions.
Until the Disappearance arc, Yuki has the ability to transport her consciousness through time by "synchronization"; however, she herself blocks this off after the arc in order to prevent errors (according to Yuki, this gives her more options for the future as well). In The Intrigues she revealed that she had given up the ability, which meant she did not know why a time-displaced version of Mikuru Asahina was visiting the "current" time plane.
- "Nagato" means "Gate Master", a possible reference to her relationship to the Integrated Data Sentient Entity.
- Nagato is in fact about 1,319 years old when one takes into account the time she's spent outside of Haruhi's universe. Her confusing short story in Editor in Chief★Straight Ahead! suggests she might be even older, perhaps having existed in a non-humanoid form prior to being made into an interface. However, Ryoko Asakura referred to her having a short three year life.
- According to some fans, Yuki does not like or perhaps even hate Mikuru, seeing her as a potential romantic rival to Kyon. This makes sense, since continuously throughout the anime, Kyon adores Mikuru for her cuteness and appeal. In The Disappearance, alternate Yuki appears to be interested in Kyon, making this theory more valid.
- Other fans believe that because of Yuki's nature as an interface and as Kyon says she doesn't have a complete personality, she would instead be envious of Mikuru, due to her lack of understanding/having emotions.