Light Yagami is the antagonistic protagonist of the series (if that makes any sense). He is one of the best students in Japan and is very popular among women. He is cold and calculating but also analytical and very mature for his age; his strong intellect combined with a superiority complex makes him see society as a set of inferior beings. Nevertheless he does not have the courage to face those who disapprove, so who excuses himself in isolation and contempt.
After finding the Death Note that Ryuk dropped on Earth for fun, and discovering its powers, his obsessions and complexes are confirmed since he believes that he is the one chosen to mold the world to an image that he approves. This is why he is disappointed when he finds out that there was no real reason for Ryuk to hand over his notebook and that it only came to him by sheer coincidence. With the Death Note he decides to make the world a better place, executing all the criminals and whoever he thinks is bad or annoying for him. Thus, he intends to create a "perfect society" and without violence in which he is the God of the new world.
After it became obvious to people that the deaths of criminals must have had an executor, his supporters named him “Kira”, a deformation of the English word “Killer”, pronounced with a Japanese accent. He, not wanting to lose, makes it be seen that he is "Kira", because of the similarity. In addition, Light knows how to “act” or interpret his emotions without others noticing, something that helps him a lot and, thanks to that, he manages to achieve the tasks he sets out to do.
Like L, Light is a genius of great potential and also wants to make his world perfect, he is greatly involved in L's investigations, being his first suspect, and, thanks to his intellect, he is then able to enter L's team. However, L never fully trusts Light.
L Lawliet is a brilliant private detective who has deciphered the most complicated cases in the world and who intends to catch Kira so to enforce the law. His deductions are brilliant. He is known in many countries for having worked in many cases, but no one knows his true identity or face. He is characterized by his big eyes, his long, black and tousled hair, eating lots of sweets – which he says make him think better – always going barefoot, walking hunched over, putting his finger on his lips and sitting down and picking up the phone in a strange way. When he is not serious, he is quite funny.
Also known as Gods of Death, they are the true owners of Death Notes, they live in a barren and deserted world. They are able to steal the life years of the person they choose to murder and can know the true name and life time left of their victims with their Shinigami eyes, a skill that can be transferred to users of the Death Note in exchange for half of the remaining life time of the victim. Although they can extend their lives, the Shinigami are not immortal, being able to die in either of the three following ways: by failing to extend their life span by not writing names on their Death Note, by using their Death Note to save the life of a human being or by carrying out an extreme offense punishable by death. According to Ryuk, when a Death Note falls into the possession of a human being, the Shinigami is forced to accompany the owner in what remains of their life or until they relinquish ownership of the Death Note.
Ryuk is the Shinigami who dropped the Death Note into the human world out of sheer boredom and who would later be found by Light Yagami; he meets Light, and as the rules dictated, he must accompany the bearer of the book until the owner dies, although that does not mean that he does not enjoy his stay in the human world, on the contrary, he entertains himself with each new situation that he experiences with Light. Something else he enjoys are all the juicy apples that he has the opportunity to taste, these being his weakness which allow L to take advantage of Ryuk in order to obtain information or force him to do or stop doing something, because if he does not eat them for a considerable period, he suffers from withdrawal syndrome: his body twists in a strange way and he suffers in the process.
At first he does not care about anything related to humans, but then he begins to be very interested in them, thanks to the behavior of Light and the subsequent holders of the Death Note. From the beginning, he told Light that he was not on either side, neither his nor L's. This is why he never told him if what he was doing was right or wrong, limiting himself to just enjoying the action and helping Light only on a few occasions when he would have also been affected. It should be noted that when Ryuk first meets Light, he tells him that one consequence of receiving the notebook is that he must stay with him until he dies and promises that he will write his name in his notebook.
Three years after the death of Light, Ryuk discovers from the world of the Shinigami that one of his companions descended into the human world to give his Death Note to a human who becomes a new Kira and only uses the notebook to kill suffering elders. He is later seen having an argument with Meadra about humans and the Death Notes once she reveals that the human she chose committed suicide after being insulted. In the film, the vision of a God is summarized; he is shown aged and weak, since, according to other Shinigami, from the moment that Light died, he has refused to write names in his notebook, so he has stopped extending his own life.