L (エル, Eru ), widely known only by the letter L, is a world renowned detective that takes on the challenge of catching the serial killer known only as Kira In his investigation. L becomes highly suspicous of Light Yagami, and makes it his goal to prove that Light is Kira.

L is a very slim, tall young man with black hair and dark eyes. One of his most noticeable features is the shadow below each of his eyes, a result of sleep deprivation. L is always shown to be wearing blue jean pants and a long-sleeved, white shirt. He almost never wears shoes or socks, preferring to go barefoot while even in public. This was shown when he visited Light Yagami's school and was seen barefoot while sitting on a bench, not bothering to wear his shoes until he got up to walk.

After meeting the Japanese Task Force, he requests that the task force refer to him as "Ryuuzaki" as an additional safety measure. The Task Force never learns his true name.

L is very intelligent, though his disheveled and languid appearance masks his great powers of deduction and many question his abilities upon viewing him. L tends to second-guess everything he is presented with, and is extremely meticulous and analytical. He is good at deceiving his opponents, and is willing to take drastic measures to solve a case. Some of his tactics are quite bold, such as having a death row inmate pose as himself on live TV in order to draw out Kira, while others seem bizarre to those involved, such as handcuffing himself to suspected-Kira, Light Yagami. He is also shown to have a dry sense of humor, and isn't above making sarcastic remarks to people. Although he tends to be polite, to some (such as Task Force member Shuichi Aizawa), L can seem quite rude and uncaring at times.

Using subterfuge, misinformation, disinformation and an analytical knowledge of human nature to help lure a suspected murderer into a false sense of security and possibly make him carelessly over-confident, whenever L gives percentages to indicate how much he suspects a person of committing a crime, such as "five percent" he may in fact be over ninety percent convinced of their culpability. Although L tells Light that he is among the least likely suspects with one of the lowest percentages of probability, in reality L is "pretty certain" that Light is Kira. As series writer Tsugumi Ohba said laughing, making light of L's tactics: "The truth is, he's a liar."

He also has several quirks, such as preferring to crouch rather than sit, eating only sweet foods (like desserts, candies and fruits) and holding items by using only a thumb and a finger. He is often seen arranging objects and very intently stacking, or in other ways playing with, his staple food items. L is almost always encountered while performing actions that are considered inappropriate or rude in public. These actions/habits include biting fingernails, placing feet on furniture, slouching, chewing with an open mouth, talking with his mouth full, calling out personal observations that may offend others, etc.

When asked about L's ethnicity, creator of the series Tsugumi Ohba responded "I think of him as a quarter Japanese, a quarter English, a quarter Russian, a quarter French or Italian, like that". Ohba said that L is the most intelligent character in the entire Death Note series because "the plot requires it". He added that he personally views L as "slightly evil".

L was found by Watari as a child and was taken to the orphanage known as Wammy's House. Sometime after, Watari realized that L had incredible knowledge and later assisted him in his cases. ^[1] L became a detective at an unknown age and eventually gained a reputation as the greatest detective in the world, whose opinion is highly valued.

L begins the Kira case by having undocumented death row inmate Lind L. Tailor introduce himself on television as "L" and say that Kira is "evil". This provokes Kira into killing the man on the spot which in turn proves to L that the Kira killings are not a coincidental succession of heart attacks amongst criminals but the designs of an ingenious serial killer who will murder any and all who try to stop him and also tells him of Kira's location, since it is only broadcast in Kanto. Not long after this, because of the time of day during which the criminals die coincide with out-of-school hours, he deduces that Kira may well be a student. He tells those assisting him with the Kira case early on in the investigation that he suspects that Light Yagami is Kira, but can not obtain any concrete evidence. In several situations, Light seems to be proven innocent by the circumstances, but L remains skeptical. If Light were Kira, the case would be solved, and L has trouble letting go of this simple and complete solution. L can easily present his conclusions publicly at any time, and due to his reputation as the best mind in the crime-fighting business, his thoughts and words are always taken very seriously.

When L introduces himself as Ryuuga, Light becomes alert and somewhat alarmed, but does not attempt to kill him - the name is conspicuously fake; however, Light has no way of knowing whether the person is the real L or a proxy acting under orders. He also reasons that L would have already introduced himself to Light's father earlier, and thus, were he to somehow kill L, this murder would instantly unmask him, proving that he is indeed Kira. If this person proved to be L's proxy, and his name really was Ryuuga, he might die, true, but L would live and know his identity, without ever having had to reveal himself to Light, so that L will have gained all the advantage. Also, while writing the name "Hideki Ryuuga" into the Death Note, the face of the pop singer bearing that name might enter Light's thoughts involuntarily, and that would cause the death of pop singer Ryuuga, which would also lead L to the obvious conclusion that Light is Kira. As such, L's expectations about the outcome of his daring opening gambit prove true, and Light finds himself in a stalemate situation, unable to act for the time being, as any attempt to rid himself of his hunters would result in confirmed suspicions, his subsequent and unavoidable unmasking, and, ultimately, his undoing. Light has no other choice but bide his time.

When L is finally able to corner him, Light puts his master plan in practice. He temporarily gives up his Death Note to his Shinigami, Ryuk, erasing his memories about his time as Kira from his mind. Rem, Misa Amane's Shinigami, under instruction by Light to give it to someone who would use it selfishly, gives it to Kyosuke Higuchiof the Yotsuba Corporation. Now unaware of the fact that he was the original Kira, Light accepts L's offer to join theTask Force to hunt down Higuchi, known as the third Kira, although he is handcuffed to L throughout the entire case. Light proves very useful in helping to track down Higuichi, realising the new Kira is connected to Yotsuba. When Higuchi is finally captured, Light touches his Death Note, thereby regaining his memory of when he was the original Kira. He then proceeds to killing Higuchi by using the Death Note paper he put in his watch before he lost his memories.

After killing Higuchi, Light then tricks Rem into killing L for his own personal gain, making her believe that she must kill him for the sake of Misa's life. L's last sight before death is Light triumphantly smiling over his defeated rival, and in his last moment L confirms to himself that Light is the first Kira. In the anime, prior to L's death Light and L talk to each other for one last time on the roof of the investigation building; some viewers believed that L, somehow, knew that his death was drawing near.

Unbeknownst to him, however, L had arranged things so that if he should die, others could take over, and consequently when his true successors Near andMello start their own respective investigations of the Kira case, Light is haunted by the memory of L whenever he communicates with them. The cooperation of Near and Mello in the Kira case eventually leads to Light's unmasking as Kira. Thus, L was able to indirectly defeat Light through his successors.

Unlike the manga and anime, in the second film, his original "death", caused by Rem writing his name in her Death Note, does not take effect, as L had written his own name in Misa's Death Note earlier. It is his self-sacrifice that allows him to stay alive for a longer duration (as he supposed that Kira would kill him on that day), and allows the investigation team to apprehend Light. After Ryuk kills Light, Ryuk offers L the Death Note. L refuses, and Ryuk, while saying that L is boring, leaves.

Twenty-three days after writing his name in the Death Note, and after burning all the remaining Death Notes and having a conversation with Soichiro, L dies peacefully while eating a chocolate bar, with a picture of Watari lying right beside him.

L: Change the WorLd choronicles the 23 days that L has left before he dies. L decides to solve one last case. He is in charge of stopping a deadly virus from spreading across the world. Ryuk comes to his aid on behalf of Kira's last wishes. Hideo Nakata, the director, told The Daily Yomiuri that he wanted to exhibit L's "human side," a quality which was not made all too apparent in the Death Note series.

Shūsuke Kaneko, director of the films, said that L's role was the most difficult to cast; as the starting date of the shooting schedule drew near, many of the "big name" actors had other projects. Kaneko decided to offer the role to Ken'ichi Matsuyama, "very much a newcomer". When Matsuyama spoke to him of his intention to "live as L", the young actor had "clinched it", declares Kaneko.

Matsuyama admits having experienced some difficulty in trying to portray L, and he worried about his performance. In the end, he decided to interpret L as an individual who does not "quite understand other people on an emotional level" - the actor reasoned that L rarely interacted with others, and as a consequence, his social skills and emotional expressiveness may not be those of a socially active person. Matsuyama, describing himself as "not very flexible physically", encountered difficulty in emulating L's postures. The actor also ate sweets that L would eat, and carefully considered the details of L's signature gestures.

Matsuyama said that he and Fujiwara became "so immersed" in their character portrayals, that they did not talk to one another while on the set; only when filming ceased did they converse, and they "went out for a drink or two."

Matsuyama described L and Light as having "such unique characters that they’re impossible to understand" and that "the inside of L’s head remains a mystery" to him. Matsuyama said that L and Light are "extremely" alike in that they have "very strong sense of justice".

In the novel Death Note: Another Note the reader is led to believe L under the alias Rue Ryuuzaki is helping Naomi Misora solve a murder case. She was recruited for the case by L because she was on leave from the FBI. This Rue acts very much like L and shared many characteristics like crouching to sit and consuming sweets. In the end of the book the reader learns that Beyond Birthday detective name B, who was an another candidate to replace L along with Near and Mello, was not only the killer but also Rue Ryuuzaki in disguise under heavy make-up. He was trying to make a case L could not solve to prove his superiority to L. In the book the only certified reference to L was the phone conversations Naomi had with him to discuss the case. In the very end of the book as Naomi was going back to work she sees a man similar to Rue, who the reader is led to believe is L (and probably is, considering that Mello earlier stated that this case was the first time that L had shown himself in public under the alias 'Ryuuzaki'). This man attempts to give Naomi a hug which she counters in self-defense and sends him tumbling down a flight of stairs. She then catches up to him and asks him his name, to which he replies, "Ryuuzaki".

It is revealed that, prior to the series, L once told Mello three stories regarding his previous solved cases — the Los Angeles BB Murder Cases, detective wars against the real Eraldo Coil and Deneuve, and the story how L met Watari.^[2]

Although following closely the storyline of its film counterpart - with the exception of a few creative changes - the novelization reveals various attributes of L. It is revealed in the novel that the initial "L" has two meanings: L stands for "Last One," meaning no one could surpass or match him, but also for "Lost One," meaning a gifted entity who has dropped down, or was cast out from heaven.

Also, in the novel, L for the first time completely loses his composure and calm attitude: when Maki is kidnapped by Blue Ship, L breaks down and screams toward the sky after realizing that this was what Light meant about feeling helpless to protect the people he cares about. L also states at one point that "his heart hurts". His feelings about Light are also revealed, and it is described that L did consider Light to be his friend, going as far as holding on to Light's broken watch as a memento and saying, "Light, I'll see you on the other side. Let us explore the world of nothingness together."

According to the timeline that is presented on each page of the novel, it appears L was to have only 272 days left to live prior to writing his name onto the page of the Death Note. Based on this bit of information it's obvious that L's remaining natural lifespan at the end of the second film would only have amounted to less than a year.

According to page 151 of the novel, it is revealed that the reason why L has acquired so many eccentric quirks is because of the heavy strain of upholding the name of L. From the novel: How L did not and could not forget the faces of thousands of victims. "Who could comprehend the man who had lived his life, and had to live confronting all the lives ended prematurely, the tears of the grief stricken survivors, the devaluing of life as a daily reality. How was it possible to measure the pain of such a man? Was it a strain so heavy that L's back curved under all its weight? Was it an agony so terrible as to leave the indelible dark circles around his eyes? Was it a feeling so bitter that every bite he took needed to be coated in sugar? The chronically rounded shoulders, the inevitable dark circles, the eccentric tastes---L suppressed the pain of being a champion of justice, but the evidence of the pain was molded into his very body."

Main Articles: Death Note: How To Read 13 and Yonkoma

Death Note: How to Read 13 describes L in the Death Note yonkoma as the "holder of the world's greatest mind" and having the "powerful ability to act like a fool". Death Note: How to Read 13 adds that in the yonkoma "it's like [L was] born to be mocked".