The main thing all Shinigami have in common is the Death Note. This supernatural notebook allows them to end the lives of humans before their times, adding the human's remaining lifespans to their own (e.g. a man who would have lived to sixty, but is killed at forty would add twenty years to the Shinigami's lifespan). In this manner, a Shinigami can extend their lives indefinitely. To assist in this, their eyes allow them to see the names and remaining lifespans of humans by seeing the faces of their victims. A human using the Death Note will not receive the same benefits as a Shinigami; while humans can kill people, they cannot increase their lifespans by doing so.
Shinigami usually pass the time by gambling with the only thing they have to trade: years of their lives.
All Shinigami must possess at least one Death Note, a necessity to extend their lives. Should they manage to come across a second, it can be loaned to a human. The Shinigami must accompany the human until they die or the Death Note is willingly given back or reach its expiration date; should the human give the notebook to another human, the same would apply to the new owner. Shinigami can explain the purpose of the Death Note to the human, but this is done at their discretion. They can also offer Shinigami Eyes to the human at the cost of half the human's remaining lifespan; however, while a human with the Eyes can also see the name and lifespan of most humans, they cannot see the lifespan of any Death Note owner, themselves included. Likewise, Shinigami cannot see lifespans of other Shinigami. In addition, Shinigami are forbidden from telling the Death Note owner their remaining lifespan, both because it would cause confusion and because a human aware of their fate might react unpredictably (in a negative way). While in the human world, Shinigami are invisible to everyone except the owner of their Death Note and anyone else who has touched it. Other unrelated Death Note users can only see their specific Shinigami. The ending of both the anime and manga state that all humans, regardless of their actions in life, go to Mu ("Nothingness") when they die, despite the misleadings earlier in the series that only humans who have used the Death Note meet this fate.
Shinigami may be male or female. Shinigami cannot and are not permitted to have sexual relations with humans; they cannot have sexual intercourse with each other, nor can they reproduce. In addition, humans cannot easily tell which Shinigami are male and which Shinigami are female. Death Note: How to Read 13 adds that Shinigami may have emotions "relating to the opposite sex." For instance Ryuk feels shy and embarrassed when Misa Amane hugs him.
Shinigami do not need to eat food; they possess senses of taste similar to those of humans; as Shinigami do not gain nutrients from food many do not eat. In addition Shinigami do not need to sleep and will not die from a lack of sleep; Shinigami view sleeping as "evidence of laziness."
The Shinigami have a language; each Shinigami has his or her own written language, with some opting for letters and some opting for pictures. Takeshi Obata, artist of the series, said that he assumes that all Shinigami can understand the languages of one another.
If a Shinigami breaks laws, the Shinigami will face one of nine punishment levels. The severity is least at Level Eight and most at Level One; in addition an "Extreme Level" exists. The Shinigami will die if a level above Level Three is applied to him or her.
Shinigami may not kill a human in any manner outside of using a Death Note; killing a human without using a Death Note merits "Extreme Level" punishment.
Shinigami have rankings, with the King of Death as having the highest ranking. How to Read 13 states that the rankings do not "seem to affect" the Shinigami's "day-to-day activities" "very much."
Ryuk is characterized by his constant amusement by, and apathy in regards to, Light's problems. He enjoys seeing Light overcome the various challenges put to him, and often waits until the worst possible moment to inform him of a certain aspect of the Death Note just to get a laugh. He is occasionally helpful if it serves his own interests, such as obtaining apples or furthering his own amusement, but for the most part will jokingly ask Light what his next move will be or have Light explain to him the point of a certain action. The sfist describes Ryuk as a "crazy-looking, supernatural creature with these wicked eyes" who becomes "(surprisingly)" a "moral compass" for Light in the film version of Death Note.
Ryuk has a great fondness for apples, comparing them to cigarettes and alcohol for Shinigami (Shinigami apples are withered and taste like sand, as he shows Misa at one point), and will go through a type of withdrawal if he goes for too long without eating them. His withdrawal symptoms involve twisting himself up like a pretzel and doing handstands. He also states that he is shy around girls. In addition to apples, Ryuk is fond of video games, first shown in the omake eight-panel comic series, where he asks for a Silver Game Boy Advance SP, originally published in Weekly Shonen Jump Volume 4-5 (double issue) in 2005. On another occasion, Ryuk asks Light if he wants to play Mario Golf (changed to "video games" in the anime), but receives no answer since Light's bedroom is bugged with cameras.
As Ryuk explains when he first meets Light, he is bound to take Light's life when his time comes. In the manga, Ryuk does this after Light is shot several times by Matsuda. He desperately begs Ryuk to write the names of the investigation team and the SPK members in the Death Note, but Ryuk just writes Light's name instead. He was expecting Light might have thought of some way out of his situation, but seeing as he was desperate enough to go to Ryuk for help, he decided it was all over for him. Ryuk returns to the Shinigami realm.
In the anime, Light does not ask for Ryuk's help and manages to escape the warehouse thanks to Mikami's suicide distracting everyone else. However, his wounds are too severe for him to escape very far, and Ryuk, who is watching him from atop a pole, writes Light's name in his Death Note. Light dies peacefully, with an apparition of L standing over him. The film ends in much the same manner as the manga, except Ryuk's silence leads Light to believe that he is willing to help. When Light learns differently, Light yells at Ryuk and jumps through him, trying in vain to stop his death before dying in his father's arms. Ryuk offers L the Death Note, but when L refuses, Ryuk moans about L being boring.
Tsugumi Ohba, story writer of Death Note, said that Ryuk is his favorite Shinigami and that "If I didn't say Ryuk here, his whole character would be in vain. [laughs]
Obata said that he encountered difficulty in creating Ryuk. He said that his original idea of Ryuk consisted of Ryuk looking like a "young man similar to Light" with black hair and wings. Obata said that he had the idea of Shinigami looking like "attractive rock stars." Obata felt that if Ryuk appeared to be more attractive than Light he would "appear to be the main character" and "things wouldn't work as well." Obata said that he decided to erase the previous design and use the final design when his editor told that Ryuk did not have to appear to be human. Obata said that he liked the "monster"-like appearance and added that, with his face, "you can never really tell what he is thinking." Obata said that he encountered difficulty while drawing Ryuk in the pilot chapter since he did not "have a good handle" on the "bone structure of his face." Obata said that during serialization he became "so used" to the underlying structure that he could visualize it. Obata describes Ryuk's face as appearing different between the pilot chapter and the actual Death Note series. In How to Read 13 Obata thought of an idea involving Ryuk's face being a mask, and under the mask would be an "attractive" face.
When designing Ryuk's Death Note Obata thought about the appearance of Ryuk's handwriting. Ryuk wrote the words "Death Note" on the cover of his own notebook, and when he took possession of Sidoh's book he wrote the same words on the front cover.
Shūsuke Kaneko, director of the films, said that he chose to create Ryuk with computer graphics as it would make the aspect of Ryuk only appearing to people who have touched the Death Note "believable" and that the audience could "tell instinctually" that Ryuk is a shinigami with "no real presence." Kaneko added that if a human actor represented Ryuk, the appearance would have been "too realistic," the actor may have impacted Ryuk's "presence," and the audience may have "doubted he was a death god, if only for a second." Kaneko ordered the graphics team to design the graphics as if it was an actor "inside a rubber suit.
Kitty Sensei of OtakuZone had her opinions of the film portrayal of Ryuk published in The Star, a Malaysian newspaper. In it Kitty Sensei said that Ryuk "looks a little artificial in the beginning." She says that she became used to the portrayal and loved "Ryuk’s gleeful chuckles and fish-faced grins.
The sfist describes Ryuk as the sole "(potential) cheeseball factor" of the first film and that he may be "difficult to get used to"; the article stated that Ryuk "adds" to the film if the viewers "let go enough to accept Ryuk's presence."
While Ryuk takes amusement in everything in the human world, Rem is almost the exact opposite. She views most humans with contempt, seeing Shinigami as the more evolved race. Also, while Ryuk is ambivalent to Light's success or failure, Rem actively assists Misa, having inherited Gelus' love for her. She is even willing to sacrifice her life to defend Misa, as evidenced by her threat to kill Light should Misa die before her time. For Misa's sake, however, she still assists Light in his schemes. Death Note: How to Read 13 said Rem "supposedly" experiences difficulty while writing the Japanese language. Also stated in Death Note: How to Read 13, Rem is female, contrary to some beliefs.
Light manages to force Rem into killing L for him by presenting a situation in which harm would come to Misa otherwise. As such, she dies when she writes L's name. In the second movie, Rem declares her love for Misa and her spite for Light moments before her death. While her Death Note is left behind in the manga and anime, she burns it in the film out of spite.
Obata said that Rem is his favorite Shinigami since she is a Shinigami and "a good person."
In the flashback, Rem recalls Gelus watching over a younger Misa Amane in the human world. Knowing that it was Misa's final day, she watches with him. Having fallen in love with Misa, Gelus uses his Death Note to kill Misa's destined murderer, against Rem's protests. Gelus is reduced to a pile of dust as punishment for extending a human life, leaving behind only his Death Note. Rem delivers his Death Note to Misa because it was her that he saved. In the film, she simply drops it and it lands near Misa. He is voiced by Ken'ichi Matsuyama and Michael Dobson in the English dub.
In the Japanese How to Read 13 book, his name is romanized as Jealous. In the English versions his name is romanized as Gelus.
Obata said that at first he placed "detailed patterns" on Gelus' Death Note. When deciding that the patterns looked "too pretty" Obata covered the patterns with black, leaving the white portions visible. The text of the notebook is in a "Shinigami language."
Sidoh shares Mello's great liking for chocolate, similar to Ryuk's liking of apples. Sidoh is fairly timid; Mello frightens Sidoh, despite the fact that Mello is a human. Death Note: How to Read 13 describes Sidoh as unintelligent and forgetful, rarely remembering the names of other Shinigami. After Light regains the Death Note from Mello, he returns it to Sidoh to keep him from interfering.
Obata described Sidoh as "very funny," citing the time when Sidoh becomes the first Shinigami to distribute flyers. Obata said he wished that Sidoh appeared more often in the story.
In the Japanese How to Read 13 book, his name is romanized as 'Shidoh. In the English versions his name is romanized as Sidoh''.
Obata said that when he discovered that another Shinigami would appear on Earth, he filed through designs and nominated Sidoh and Daril Ghiroza. Obata said that he believed that Ghiroza would be chosen and prepared for that decision; instead Ohba selected Sidoh. Obata said that he based Sidoh's design on the appearance of a bird with his mouth being based on a beak of a canary. Obata described Sidoh's foldable arms as more "insect-like."
As described in How to Read 13, Justin is the right-hand man of the Shinigami King and sits on a throne. Highly intelligent, Justin knows everything there is to know about the Death Note. Obata describes him as "conceited." Justin provides Sidoh with several scrolls describing the various rules that Shinigami have for interacting with humans, which Sidoh uses to guide his interactions with Mello in the human world. The scrolls are not mentioned in the anime.
In the Japanese version his name is Armonia Jastin Beyondllemason.
Obata said that he based Calikarcha's design off of Balinese bird masks.
Obata described her as "more of an Orthodox-looking Shinigami." Obata said that since Obata designed her at the same time as his design work for Sidoh for use as a new main character he gave her some contrast with Sidoh's design. Obata said that he based Ghiroza on Ryuk's design and tried to make her appear "higher-ranked." Obata said that when he discovered that another Shinigami would appear on Earth, he filed through designs and nominated Sidoh and Daril Ghiroza. Obata said that he believed that Ghiroza would be chosen and prepared for that decision; instead Ohba selected Sidoh. Obata said that the reason why Sidoh was chosen is that Ghiroza attained a high Shinigami rank and therefore would not fit the role of a Shinigami being "pushed around" by a human being. Obata said that he was glad that Ghiroza was not selected since her design included many details that he felt would have caused "real trouble" if he tried to draw her in every chapter.
In the Japanese version her name is Dalil Guillohrtha.
Obata said that he based Deridovely on a "gross-looking transparent insect." Obata believes that the bandages aid the design.
In the Japanese version his name is Dellidubbly.
Obata said that, as Gukku appears in the first chapter, he wanted for Gukku to "look like a monster to keep it simple." Obata decided to use a cattle skull in the design as he felt that using a "regular skull would be boring."
In the Japanese version his name is Gook.
Obata said that, since the final volume release pended, he wanted to create a new Shinigami to appear in the volume.
Midora appears to have the same feeling toward bananas, as seen in one panel of the one-shot when she is in the new Kira's room, she is eating a banana while lying amongst an enormous pile of banana peels. In the Death Note: How to Read 13, her name is Midora. In the Japanese version her name is Meadra.
Obata said that he liked Midora's design as she appears "more like a salamander" and has a "vastly different" design when compared to other Shinigami. Obata said that her skin feels moist like amphibian skin; due to this Obata said that he worries "if she can survive in the heat of the Shinigami realm. [laughs]"
Obata described Nu as like "a giant rock covered in eyes that sticks out of the ground." Obata said that Shinigami like Nu exist and are "rare."
One of the eyecatch rules given in the series states that extra Death Notes found by Shinigami are generally expected to be returned to the King, though this clearly is not something Shinigami are forced to abide by. Likewise, lost notebooks must also be reported to him. Little information is given about the character itself, aside from Rem's assertion that the King is not easy to trick, which Ryuk successfully did. In contrast, he is quite easily bribed, as Midora was able to trade thirteen apples for a second Death Note.
Obata said that he felt too afraid to design the King of Death; he said that he considered placing the King of Death on a book spine but felt that the spine would not have enough space to depict the King of Death.
Obata said that he used a Native American motif for Zellogi. Obata said that after covering his eyes and adding feathers "the rest just came naturally. [laughs]"
In the Japanese version his name is Zerhogie.