“If we catch Kira, he is evil. If he wins and rules the world, then he is justice.”
Light Yagami (夜神月, Yagami Raito) is the main protagonist of the Death Note series. After discovering the Death Note, he decides to use it to rid the world of criminals. His killings are eventually labelled by people of Japan as the work of "Kira."
Light is a young man, standing at above average height with light brown hair and brown eyes. He tends to dress very neatly and formally, often seen wearing his school uniform or a suit. He is considered to be quite handsome, a trait noted by Misa Amane and Kiyomi Takada, among others.
Light is characterized as hardworking, talented, and a natural genius. Light would constantly predict all of the possible scenarios that could happen and plan a solution in advance, even in the most impromptu situations. His faults include his cynical outlook on life, overconfidence in himself, and belief that he is never wrong.
He is frustrated by the lack of justice in the world. Believing the world to be "rotten," he uses his Death Note as a means by which he can enact his will to rid the world of evil people. Light's main goal is to create a new world that is free of injustice and populated only with honest and kind people, thus becoming the "God of the new world". Light is decisive and driven to achieve his ambitions, without faltering one bit in his beliefs. Despite staining his hands with the blood of the people that he's killed, this extreme action can be said as a result of his unmoving resolve.
Through use of the Death Note, Light quickly begins to develop a cold, ruthless, and malevolent nature. He becomes completely devoid of love, compassion, and mercy. He views himself as the only rightful savior of mankind and that all his actions are justified, no matter how inhuman they might be. He is shown to even be willing to sacrifice his own family, if pushed to that point. The fact that he is intelligent also adds to his notion that only he is fit to judge humanity and steer it on a proper moral course.
Throughout the series, Light is constantly trying to evade the suspicion of L and other detectives while both maintaining his identity as "Kira"—the name derived from the Japanese pronunciation of the English word "killer" (キラー, Kirā)—and cleansing the world of crime.
Light grew up in Japan with his family, which consists of his father, Soichiro Yagami, who is a member of the Japanese Task Force (an investigation team opposing Kira), his mother, Sachiko Yagami, and his younger sister, Sayu Yagami.
At the start of the series, Light is a third-year high school student (12th Grade) at Daikoku Private Academy and also attends supplemental classes at Gamou Prep Academy in the beginning of the story. He later attends college at To-Oh University (東応大学, Tōō Daigaku).
Finding the Death Note
In the year 2003 (2006 in the anime), Light Yagami discovers a mysterious notebook on the ground at his school. Written on the cover are the words "Death Note". The Death Note's instructions state that if a human's name is written within it, that person shall die. Light is initially skeptical of the notebook's authenticity, but after experimenting with it, Light realizes that the Death Note is real.
After putting much thought into whether or not he should continue using the notebook, he ascertains that no one else will be able to bear the burden of improving the world. Light then meets the previous owner of the Death Note, a Shinigami named Ryuk. He explains his reasons for dropping the Death Note in the Human World, and when it is Light's time to die, he will be the one to write Light's name in his notebook. Light then tells him of his goal of getting rid of all the evil people in the world, and ruling over it as God. Ryuk responds by saying, "It's just as I thought, humans are so interesting!"
Light's killings reach a monumental scale, attracting the attention of the master detective known as L. The first conflict between Light and L happens over the television, beginning with the broadcast of Lind L. Tailor. L places Tailor as a decoy on television in order to trick Light. The network states that the broadcast is worldwide and that Tailor's statements (made in English) are being translated into Japanese by Yoshio Anderson. Light anticipated that the police would get involved and calls him foolish for thinking he can catch him, because as long as he doesn't get the notebook, there won't be any evidence to convict him.
After Tailor says that he is "L," he reads a declaration stating that Kira is evil. Light, in a rage, yells that he is justice and will become the God of a new world that everyone desires. He kills Tailor with a heart attack, saying that the ones who fight against God are the ones who are truly evil.
Light thinks the ordeal is over, but the broadcast of Tailor is suddenly cut, and L's signature letter 'L' appears. Using a voice synthesizer, the real L announces that Lind L. Tailor was a decoy and a criminal on death row. He explains that Tailor's information was never made available to the public, so there was no way Kira could have killed him until now. L boldly taunts Kira, asking him to try to kill him, as Light stares at the TV, angrily shocked that he's been fooled. After several seconds, L learns that Kira needs the person's real name and face to kill the victim, otherwise Kira would have already killed him. L announces that the video was aired only in the Kanto area of Japan as a ploy to determine the location of Kira. L, originally planning to air the video in other areas in Japan at different times, stated that it would not be necessary to continue broadcasting Tailor's footage. L says that he is now speaking directly to Kira and tells Kira that he will catch him, then the broadcast ends.
Ryuk found the whole thing before him quite entertaining. As Light ponders over this, he accepts L's challenge to him. He also declares that he will find L and he will eliminate him. The two announce their intentions, and both declare that they are "justice".
The FBI Agents
Soon after, now working with the Japanese police, L begins to lead a Task Force alongside Light's own father, Soichiro, in order to expose and capture Kira.
As Light walks home from school, Ryuk tells him that he is neither on his side or L's side. However, Ryuk feels like he should tell Light that during the last couple of days there has been a man following him. Light is surprised, but he feels that the investigator doesn't know that Light is Kira. Regardless, Light is determined to find out the man's name without looking too suspicious.
Ryuk tells Light the purpose of the Death Note. A Shinigami gets extra life from killing humans with a Death Note, which is why a Shinigami can live for many years and cannot be killed in any other way. However, Shinigami are apathetic when it comes to the human world, and they sometimes forget to write down names for centuries. Then, Ryuk explains to Light that the Shinigami have eyes that allow them to see any human's real name and lifespan over their head. In addition, a Shinigami can make a deal with the owner of the Death Note to receive the "Shinigami Eyes" in exchange for half of that human's remaining lifespan. Ryuk mentions that he can see Light's lifespan, but he is not going to tell him how many years he has left because he is neither on his or L's side. Ryuk offers to make a deal with Light for the "Shinigami Eyes". Light refuses the deal, stating that he needs to live for a long time in order to rule over his utopian world. He asks Ryuk if there is anything else that he should know about the Death Note, and Ryuk says probably not.
Suddenly, Light has an idea about how to find out the FBI agent's name. He decides to use his stock criminals in order to find out how specific the details of death need to be.
Light boards a bus with his date, Yuri, and Light's follower takes a seat behind the couple. Soon after, a man boards the bus. The man pulls out a gun and points it to the driver, taking the bus hostage. The bus driver is forced to call Space Land (the amusement park the bus is headed to) and report the situation. The bus driver explains that he is being held at gunpoint before the bus-jacker takes the phone. The bus-jacker says that the driver is telling the truth and to bring the financial reports of Space Land to the bus stop that is before the stop prior to reaching Space Land; if they call the cops or do not comply, he will kill everyone on the bus.
Light shows Yuri a note telling her that she should not worry, and he will attack the bus-jacker's hand that's holding the gun. Light's follower sees the note and tells Light not to do that, telling them that he will handle the situation himself. Light begins writing on a piece of paper, and Light's follower tells him that he doesn't have to write notes, because the bus-jacker can't hear their voice over the sound of the bus. Light crumbles the paper and puts it in his pocket, then tells his follower that he can tell from his accent that he isn't Japanese. The man says that he is Japanese-American, and Light replies by asking him if he can prove that he isn't the bus-jacker's partner. Yuri reacts in disbelief and Light explains to her that a tactic criminals use is to have one criminal act while the other hides and waits in secret, appearing as a bystander. Light asks again if he is the bus-jacker's partner. The man, thinking that Light is not Kira or he would have killed the criminal by now, decides that he has no choice; he takes out an FBI badge and shows it to Light, revealing that his name is Raye Penber. Light says that he believes him, but that he doesn't know why the FBI is there in Japan. Light asks Penber if he has a gun, to which he responds yes. Light replies that he will leave the situation to him.
Light puts his hand into his pocket, then takes it back out, causing his piece of paper to fall onto the floor. The bus-jacker watches as Light tries to pick it up and yells at Light to not move. The bus-jacker picks up the paper and thinks that they are passing notes. Penber recognizes the paper as the one that Light showed to Yuri and becomes worried. Penber puts his hand into his jacket, seemingly to reach his gun. However, the bus-jacker laughs and throws the paper back at Light, believing it to be a note inviting someone to Space Land. The bus-jacker tells everyone to not make any sudden movements or else, then turns around and suddenly begins screaming in panic, asking what that "thing" is at the far back of the bus. He begins asking it when he appeared, and Ryuk replies by asking if he is talking to him. Ryuk asks the bus-jacker if he can see him, and the bus-jacker, appearing scared, tells Ryuk to not move or he will shoot him. Penber says that the bus-jacker is hallucinating and warns everyone on the bus to get down. Ryuk, finally understanding Light's plan, notes that Light intended for the bus-jacker to pick up a piece of the Death Note. The bus-jacker begins shooting at Ryuk, and Ryuk says that bullets cannot kill a Shinigami. As the bus-jacker continues to shoot, Ryuk notes that he told this to Light, and thinks it clever that Light had constructed this situation to reveal the name of the man that has been following him. Penber sees that the bus-jacker has used up all of his bullets and prepares to act. However, the bus-jacker flees the bus onto the road, where he is immediately hit by a car.
Light begins exiting the bus, and he finds Penber waiting for him. As Light exits, Penber tells Light that he is on a secret mission. Light says that he understands and will not tell anyone that they met, not even his father. Penber smiles before telling Light that he is leaving because things could get complicated if he is here when the police come.
Back at Light's house, Ryuk asks him if he's going to write Penber's name down in the Death Note. Light tells him that it would look too suspicious if he does so immediately after they met. In addition, he wants Penber to show him the names and faces of every FBI agent sent to investigate the NPA.
On December 27, 2003, Light goes to an underground section of the Shinjuku Station. Ryuk asks Light what he plans to do, and Light says that he's going to show him the results of the experiments he's done over the last six days. Light reveals that he has been experimenting with the Death Note and has found several new ways to kill. Light figured out that he can write the date and cause of death in the Death Note without a name, and the Death Note will work when the name is added later. At 3:00 PM, while wearing a hood to obscure his identity, Light holds Penber hostage in an underground section of the Shinjuku Station. Light appears behind Penber (unaware that it is Light) and tells him that he is Kira, instructing him to not turn around. Light says that he will prove his identity by killing Yonegoro Nusumi, an employee at a shop labelled "Cafeel" with a heart attack. The shop employee dies, and Light explains to Penber that Nusumi had raped women but escaped a court conviction due to a lack of evidence. Light then says that he is purifying the world and believes L has already told Penber that he can't kill without a name and face, but Light says that he can kill anyone in this station. Light asks Penber if he needs to prove his identity, and Penber responds that he believes the man is Kira. Light says that there must be someone more important there that would make a great hostage, and Penber asks if he means "her". Light tells Penber that he is correct and explains that he has done a background check on his family. Light threatens Penber by stating that non-compliance would lead to his death, the death of his love, and the deaths of his family.
Light asks Penber if he's carrying a laptop, and if he has a file containing the names of all of the FBI agents in Japan. Penber says that he doesn't have a file like that, and Light hands him an envelope. He tells Penber to hold onto the envelope, take out the transmitter and put the earphones in. Over transmitter, Light leads Penber through a turnstile in the western entrance at 3:11 PM. He tells him not to look around when he gets on the train and to remember that he is at Kira's mercy. He says to sit near a window and to wait for a seat to open if there are none available. Penber enters a train on the Yamanote Line at 3:13 and takes a seat as Light tells him to truthfully answer a question, stating that if he lies, he will kill his fiancée. Light asks how many FBI agents there are, and Penber says that he thinks there are four groups, totaling twelve agents. Light says to call an agent that is ranked lower than him and ask for the names and faces of all agents sent to Japan. Light states he needs to be able to hear the conversation. Penber uses his cell phone and calls an agent, and then asks him for the name and faces of the agents. The agent asks Penber why he doesn't ask his commander, and Light tells Penber to say that the connection between their computers is bad, and it would be better to use someone else's computer. Penber receives the FBI file at 3:21 PM, and Penber is the second FBI agent that receives it. Light tells Penber to take the contents out of the folder he gave him, and Penber takes out four envelopes with ten rectangular spaces cut out of the left side of each one. Light says to write down the names of the agents into the blocks on the folders. As Penber writes, Light tells him not to get off of the train when he's done, and that if he follows his instructions his fiancée and family will not be killed. As Penber finishes, Light says to put the transmitter and envelope back into the folder and sit quietly for thirty minutes, then place the envelope above on the rack and leave the train when no one will notice. At 4:42 PM, Penber dies from a heart attack three seconds after he exits the train, and he turns around to look back onto the train. Penber appears shocked as he looks at Light's face and says, "Light Yagami." Light watches as Penber dies, and tells him, "Farewell, Raye Penber."
Light takes the files home and takes the pages of the Death Note out of their envelopes, revealing the times and causes of death for each agent. Each agent will receive the file and die at a different time.
Light's father holds a family meeting in their kitchen, three days before the New Year, and announces to Light, Sachiko and Sayu that he is working on the Kira case. Soichiro says that twelve FBI investigators were killed, and Light asks if they were killed by Kira. Soichiro says that it appears that way, saying that the Kira case is dangerous. He also mentions that many officers have left the investigation, and he could think of no reason to make them stay. Worried, Sachiko suggests to Soichiro that he quit the investigation, and Sayu also says that he should quit because she doesn't want him to die. Soichiro tells them that he will not give up or back away from crime. Light tells his father that he thinks what he's doing is admirable and says that he supports him. As Light walks from the kitchen, he tells his father that if anything happens to him, he will personally put an end to Kira. Light shuts the door leading to the downstairs area of the house, and begins to climb the stairs leading to the second story. Ryuk tells Light that his acting is good, as well as his method of killing the FBI investigators.
Light's next threat comes from an unexpected person: Raye Penber's fiancée. After the sudden death of Raye, Naomi Misora decides to take part in the Kira case herself. Having been told by Raye that he showed his FBI badge to someone during a bus-jacking, Naomi deduces that Kira must have been on the bus. In her attempts to contact the Japanese Task Force, she comes across Light Yagami. Light uses his father's status to his advantage, telling Naomi that he is Chief Yagami's son, which allows him to slowly win her trust. Cautious at first, she uses the false name Shoko Maki in order to protect herself until she can reach L.
After he realizes that this was an alias from the way Ryuk laughed, Light finally gets Naomi to reveal her name by saying that he is a member of the Task Force and is actually working with L. Taking advantage of Naomi's emotional state, Light gives the possibility that she could join the Task Force and help catch her fiancé's murderer. Light says that he will need to see a form of identification before she can join, and Naomi shows him her driver's license. Using a piece of the Death Note, Light writes down Naomi's name, resulting in her death by suicide. Her body is never found due to the specifications made by Light in the Death Note.
The Second Kira
On April 22, 2004, in a broadcast on Sakura TV, "Kira" sends tapes stating that if criminal reports stop, Kira will kill police officers and reporters, and then demands that the life of someone in charge of the Kira investigation be handed over—the Director's or L's. "Kira" says to choose one and reveal them in four days and that, because Kira knows the Director's face, there are no special requirements; however, if they should choose L, he must appear on Sakura TV's 6 o'clock news and give a ten-minute speech. "Kira" says that they will decide if the person on the news is L, and if it is decided that he isn't, Kira will take the lives of several police officers as compensation. "Kira" says to please not lie as Kira does not wish to kill those without sin, and to think carefully over the next four days.
Light Yagami watches the broadcast and laughs, amused, as Ryuk watches with a grin on his face. Light asks Ryuk if this is the work of another Shinigami, and Ryuk says that it likely is. Light responds positively to the idea that the owner of the Death Note is supportive of his ideals, then says that he is the only one who knows that this new Kira is fake. Light decides that he needs to find a way to use this new Kira to his advantage, then says that the new Kira likely has the Shinigami Eyes based on how the person killed the police officers, and is therefore more powerful. Light decides that he can use the new Kira to prove his own innocence and get rid of L at the same time, and then states that the new Kira's actions have also been damaging Kira's reputation, and if he gets caught by the police, it could be troubling for Light. Light says that the best course of action for him to take is to find a way to get on the Task Force so that he can keep an eye on L and the new Kira, and that it should be simple because L did not reject to him joining the Task Force earlier. Light states that if the new Kira ever messes up, he can just kill him and take the new Kira's notebook before L does, although it would be favorable if the new Kira just killed L in four days. Light decides to find a way to contact the new Kira without revealing his identity in order to take control of him.
A few days later, after observing him from monitoring his household, L decides that he wants Light to help the Task Force. L has Soichiro call Light and tell him to come immediately if he agrees to join them. Light arrives at the hotel and appears surprised at the small size of the Task Force, and L tells Light that there are a few outsiders who know what happens within the investigation and only one can contact L directly. Light thinks to himself that if everyone in the Task Force dies but one, the killer is revealed. Therefore, he must find out who the outsider with the information is. Light is told to look over the papers of the investigation and then watch the tape without taking notes or removing anything. As Light watches the tapes, he begins thinking that he wants to throw up and wonders if it's because he is the real Kira. After watching the tapes, Light says that there may be someone else with Kira's abilities, citing the difference in criminals killed, as well as the fact that some were killed immediately after revealing their faces.
L reveals that he came to the same conclusion, and Light asks if L was testing him. L denies that he was and tells Light that he was the only one who thought there could be an another Kira, and he needed Light to think of the same idea without his opinion. Light realizes that L would have told him his plan regardless of what he told L and that he set things up so that if Light didn't say there was another Kira, he would look suspicious, and if he did, he would help prove L's theory to the Task Force. L asks Light to help their case by pretending to be Kira and tells Light that only he is able to play this role, starting with writing a draft for the speech as Kira. When Light is through, he asks L if his draft is good, and L says that it is, but if he doesn't remove the part about it being okay to kill L, he'll die. Light laughs and says that he was kidding, adding that it's fine to remove it, and L gives the draft to Aizawa to take care of. Later, the tape is created and sent to various TV stations. The Second Kira responds with videos which contain indirect, and some rather direct, comments about Death Notes, Shinigami, and how they can meet. Light goes to Aoyama to find the Second Kira, but he is unable to meet this Kira. However, due to having Shinigami Eyes, the Second Kira is able to identify Light as Kira due to being unable to see Light's life span.
After finding out his address, the Second Kira arrives at Light's house, telling his mother and sister that she has his notebook. Light invites Misa to his room and asks Misa to explain her actions. Misa says that she wanted to meet Kira because her parents were murdered in front of her, and Kira killed the man who did it. Misa asks to be his girlfriend and partner, admitting that she wouldn't even mind if he simply uses her. Light agrees, intending to kill her after she outlives her usefulness. However, Misa's Shinigami, Rem, promises to kill him if he ever harms Misa.
After L found DNA evidence in Misa's room that is connected to the Kira tapes, her reckless actions put both her and Light in danger, thus allowing L to finally corner Kira. Deciding to manipulate Rem, Light puts his master plan into action. He temporarily gives up his Death Note to Ryuk, erasing his memories about his time as Kira.
Rem, under instruction by Light to find someone who would use the notebook for selfish means, finds Kyosuke Higuchi of the Yotsuba Corporation.
Now unaware of the fact that he was the original Kira, Light accepts L's offer to join the investigation team to hunt down Higuchi, who has taken up the mantle of Kira. During the investigation of Yotsuba, Light works under the alias "Light Asahi". When Higuchi is finally captured, Light touches his Death Note, regaining his memories of being the original Kira. He then kills Higuchi by using the Death Note paper hidden in his watch to effectively become the owner of the notebook again.
The End of L
Later, he is able to put Misa in danger again by having her act as Kira in his stead, prompting Rem to kill both Watari, L's closest partner, and L himself in order to save Misa. Shortly after L's death, Light is nominated by the Task Force (who are unaware that he is Kira) to act as L, deciding not to publicly reveal L's death.
After winning the battle with L and taking his persona, Light gains control of the Kira investigation team. This puts him on the safest ground as his role as a second generation L, covering his identity as Kira.
For the next five years, by using L's database of criminal records, Light's judgments become more widespread than ever. As a result, the world falls into a dark age in which essentially everyone now lives under the law of Kira, or as L puts it in Relight 2, "in which Kira's will is the only law."
Mello and Near
At the age of 23, Light joins the Japanese Police Force's Intelligence Department in order to have better access to police information.
Near and Mello, the "true successors of L" eventually appear before him, trying to accomplish what L could not: exposing Kira's true identity and bringing him to justice. Near joins the Special Provision for Kira (or the SPK) for help in his endeavor, and Mello decides to use the Mafia for his investigation. Because of Mello's unscrupulous, criminal methods, Near sides with Light, not knowing that the latter is Kira. Mello is able to at one point take the notebook away from Light, but the combined efforts of Light and Near allow Light to regain the notebook at the cost of his own father's life (which Light would later explain to have been a necessary sacrifice).
Once Near realizes that Light was responsible for the lack of progress in the case as the new L, he begins to suspect that Light may in fact be Kira. With a prosecutor named Teru Mikami acting as a new proxy, Light formulates a plan to eliminate not only Near but the surviving members of the Task Force and the SPK as well. Near, likewise, forms his own plan to finally expose Light as Kira. However, Mello intervenes and manages to cause Mikami to make a mistake, smashing Light's plans into the dust.
Light, Mikami, the SPK and the Task Force all eventually meet at the Yellow Box warehouse, where Near uses Mikami to expose Light as Kira. After confessing and attempting to justify his actions to the people tasked with capturing him, Light tries to kill Near with the notebook clipping hidden in his watch, only to be shot by Touta Matsuda, a member of the Task Force.
In the manga version, Light is left incapacitated both physically and mentally. Light yells for Mikami to write down the names of everyone present, but Mikami responds by asking how he is supposed to kill them with a fake notebook. This brings Mikami to the realization that Light is not "God". Light becomes increasingly distraught and begins asking for help from Misa, only to be told by Aizawa that she isn't here. He then asks for Takada and is told that she is dead. In complete desperation, Light begs Ryuk to help him by killing everyone in the room, yet Ryuk reminds Light that he is on neither side. Ryuk fulfills his promise from the beginning: he writes "Light Yagami" in his Death Note, and Light futilely asks Ryuk to reverse the process. He begins to panic, repeating in his head "I don't want to die," before the Death Note finally takes effect thus killing him.
In the anime version, Mikami commits suicide by stabbing himself with his pen and losing a lot of blood, creating a diversion for both the Task Force and the SPK. Although weakened, Light catches a second wind and manages to flee the warehouse. Near tells Aizawa, Mogi, Ide, and Matsuda that there is no reason to pursue Light given that there should be no more hidden Death Note pieces and Light's wounds would prevent him from getting far. Aizawa refuses to heed Near's orders and has his team follow Light. Meanwhile, Ryuk writes Light's name down when the latter finds another warehouse to hide in. As Light silently dies, an illusion of L appears before Light, mirroring a scene following L's defeat at Light's hands in episode 25.
At the end of Death Note Relight 2: L's Successors, Aizawa and Matsuda are revealed to have found the warehouse Light has fled to; their expressions of shock imply that they have seen Light's body.
In other media
In the film, a few changes were made to Light. At the film's beginning, Light is a first-year university student studying law instead of still being a high school genius like in the beginning of the manga and anime. Light's motives differ; his boredom trait does not exist, and he instead uses the Death Note out of frustration from the perceived failures of the Japanese justice system. Light, prior to his discovery of the Death Note, hacks into the government database and finds that the government secretly acknowledges that many criminals can't be prosecuted. Light discovers the Death Note in an alley during a rainy night after encountering Takuo Shibuimaru in a club and throwing a law book into the rain in a rage. Light meets Ryuk after killing Shibuimaru. Light has a girlfriend, Shiori Akino, who attends his university. Light kills Shiori at the end of the first movie to gain sympathy from L (character) using Naomi Misora, whom he also kills.
After Rem "kills" L and Watari, Light writes his father's name in an attempt to kill him, an attempt that ultimately fails. The endings of both the second movie and the manga are similar. In the second film, after being exposed as Kira, Light asks Ryuk to write the names of the team members in the book during the climax. The police shoot but do not kill Ryuk as he writes in the Death Note. Light laughs until Ryuk shows Light the Death Note, revealing that Light's name was written in the book. Light tries to stop Ryuk, passing through the Shinigami. Light dies in his father's arms, begging him to believe that he acted as Kira to put justice into practice: justice, which Soichiro Yagami had taught Light since his childhood. The film concludes one year later on Light's birthday. Sayu fetches Soichiro and says that Kira helped reduce crime rates. However, she says that she does not support Kira as Light was killed by Kira (which is what Soichiro told her). Light is portrayed by Tatsuya Fujiwara, known for his role as Shuya Nanahara of Battle Royale.
Conception of Light in the films
Shusuke Kaneko, director of the film, intended for Light to appear sympathetic at the beginning of the film; when Light first gains the Death Note, Kaneko "was careful" to have Light react in a manner "as you and I would." Kaneko changed the story involving Light gaining his first notebook as he felt that the audience "would have a hard time sympathizing" with Light if the scene remained the same as it was in the manga. Kaneko added that as he portrayed Light as "being enthralled" as he "becomes more cruel" to make the audience members feel that they could "do the terrible things he does" even if the members do not sympathize with Light.
Kaneko designed Light's room to reflect the character's personality by making it clean and neat and filling it with legal, criminal history, foreign, and academic books. The original version of Light's room included a stereo; Kaneko replaced it with a vacuum cleaner to reflect Light's "clean-freak self."
Tatsuya Fujiwara said that he felt difficulty portraying Light in the film series because of the lack of "action" and because Light has no signature mannerisms and therefore has his feelings displayed by his face; Fujiwara added that he struggled conveying Light's "incredible amount of intelligence" and that the performance would appear "very empty or simplistic" if Light received an improper portrayal. Fujiwara explained that he wanted Light to cry in a particular scene even though Kaneko told Fujiwara "Light doesn’t cry" since Fujiwara believed that the scene would feel "more honest"; Kaneko used the take. Fujiwara said that he "could understand" Light's intentions to create a new world even though "murder is a horrible thing."
Light receives major character changes in the Japanese drama. At the beginning of the series, Light is an average college student who works part-time at a pub. Light wishes to become a civil servant and shuns the idea of becoming a police officer. He is also a fan of Misa Amane, and he regularly attends her concerts. He is far more prone to emotional outbursts compared to his manga counterpart, often crying when he feels cornered by L.
Due to his decreased intelligence level, Light proves to be much less competent as Kira than his other counterparts. For instance, instead of mining data about the Kira Investigation from his father's computer, Light just asks Matsuda or his father about details pertaining to L and the investigation. His plan to kill Raye Penber and the FBI agents is also botched when the latter sees through the plan.
Light is very similar to his canon self in the musical, and the story approximately follows canon up through Misa's confinement. Light does not volunteer for confinement, and the final confrontation with L happens soon after instead.
Light is portrayed by various actors for the different musical productions. Kenji Urai (浦井健治) and Hayato Kakizawa (柿澤勇人) shared the role in the 2015 Japanese production, and they will both reprise the role for the 2017 Japanese production. Hong Kwang-Ho (홍광호) portrayed the character for the 2015 Korean production, and Han Ji-Sang (한지상) is taking over the role for the 2017 Korean production. Jeremy Jordan voiced Light for the English-language 2014 New York studio demo recordings.
Light performs the following songs in the Musical:
- "Where is the Justice" is sung by Light and his high-school classroom. Light also sings the first reprise after embracing his role as Kira.
- "Change the World" is the song he sings when he jokingly writes a criminal's name in the Death Note for the first time.
- "Death Note," aka "Hurricane," is the song Light sings once he realizes he has killed someone with the Death Note.
- "Don't Cross That Line" is a song Soichiro sings about his disapproval of L's methods with Lind L. Tailor. Light joins in as well.
- Secrets and Lies
- "Stalemate," aka "A Game of Death," is a song between L and Light at the Todai University entrance ceremony. Misa also joins in for a verse.
- "Playing His Game," aka "Into Him," is a song between L and Light during their tennis match.
- "Last Moments" is a song between L and Light during their final confrontation.
The following information is from Death Note 13: How to Read.
Tsugumi Ohba: Writer
Takeshi Obata: Artist
Ohba said that Light was "a young man who could understand the pain of others" when he first encountered the Death Note. Ohba said that if Ryuk never developed an interest in the human world, Light would have become "one of the greatest police leaders in the world" who, with L, worked against criminals. Ohba described Light's life as "ruined" once he obtained the Death Note, and that Light became a victim of the Death Note "in many ways". Ohba described Light as bearing good faith intentions and having a "very conceited" nature. Ohba also describes Light as having a "warped" "desire to be godlike," bearing love for his family, and intending to transform the world into "a better place". Ohba added that he believed that debating whether Light's actions were good or evil is not "very important." Ohba says that he personally sees Light as a "diabolical" character.
According to Ohba, Light sees Misa Amane, who he uses as an accomplice, as a "bad person" who killed people, so he acts emotionally cold towards her and manipulates her. Despite this, he keeps her alive even after her memories of being Kira have been removed for the second (and final) time.
Ohba said that his editor suggested the family name "Yagami" for Light. Ohba said that he did not feel "too concerned" about the meaning of the name (the kanji are "night" and "god"); he said that after he created the final scene in the manga he "liked" that the final scene created "deeper significance" in the name.
Obata said that he had "no trouble" designing Light as the character description presented to him, "A brilliant honors student who's a little out there," was "clear and detailed." As the weekly serialization continued, Obata simplified the design by unconsciously removing "unnecessary" lines and felt that he became "better" at drawing Light. When Chapter 35 appeared and the editor informed Obata that Light lost his memories, Obata felt that he had to "forget everything he learned" and draw Light in a similar manner as he appeared in Chapter 1.
Obata said that he used "a lot of effort" to design Light's wardrobe. According to Obata, he encountered difficulty imagining the clothing of "a brilliant person," so he looked through fashion magazines. Obata envisioned Light as a "smart and formal guy" who wears formal shirts. Most of Light's clothing in Death Note is "fitted" and Obata avoided jeans.
When designing color book covers, Obata assigned colors to characters to "get the atmosphere right." Obata assigned clear or "lack of a color" to Light.
When asked about which character was most similar to himself, Ohba indicated Near and "maybe Light." Regarding Light, Ohba cited "because I did well in school." Obata said that Light was his second favorite human character and that he was not sure whether that was because he "liked" Light or because he drew "such a diabolical character" in a magazine for children.
- The name Yagami literally means "night god."
- Light is portrayed in a crucified-like position on the twelfth and final manga cover. This position is mimicked by Light during the second ending sequence in the anime and again when he is portrayed as a secret Nendoroid figure for the Death Note Case File merchandise line. This position connects to Light's desire to be a Messiah figure of the human race similar to the Christian Messiah, Jesus Christ.
- In the anime, certain characters take on stylized hair colors while the viewer hears their thoughts; Light's color is red.
- In Death Note Relight 1: Visions of a God, an unnamed Shinigami appears in the Shinigami Realm. This new Shinigami asks the others where the Rogue Shinigami named Ryuk is. Some members of the fanbase believe this unnamed Shinigami to be the reincarnation of Light Yagami (more information about this can be viewed on the Myths page or on the Light's Reincarnation Theory over at the Death Note Fanon Wiki).
- Light is one of the Death Note characters that were made into Nendoroid figures. The Light Nendoroid comes with small Death Note and a pen which he holds and three faces: a laughing face, an angry face, and a normal face.
- “I'm going to make the world know I'm here… that somebody is passing righteous judgement on them.” (Chapter 1)
- “I will reign over a new world.” (Chapter 1)
- “"I'll make you trust me. And when you've told me everything I need to know, I'll kill you.” (Chapter 19)
- “You can't ever win if you're always on the defensive, to win, you have to attack.” (Chapter 20)
- (To Ryuk, regarding the Death Note) “I've never considered finding that notebook and gaining that power a misfortune.” (Chapter 22)
- “This… is the first time that I actually want to punch a girl.” (Chapter 31)
- “I'm going to get more intimate with Misa and make her fall helplessly in love with me.” (Chapter 32)
- “The thing I hate the most is to trample on other people's good will.” (Chapter 37)
- “Exactly as planned.” (Chapter 53)
- “Follow the teachings of God and receive his blessings, and so it shall be that the seas again become bountiful.” (Episode 1)
- “I'll solve equations with my right hand and write names with my left. I'll take a potato chip… and eat it!” (Episode 8)
- “Under normal circumstances, humans should have continued to evolve as the greatest creatures upon this earth, but we were actually regressing. A rotten world. Politics, law, education… Was there anybody around who could correct this world? But someone had to do it.” (Episode 37)
- “I understood that killing people was a crime. There was no other way! The world had to be fixed! A purpose given to me! Only I could do it. Who else could have done it, and come this far? Would they have kept going? The only one… who can create a new world… is me.” (Episode 37)