Ryuk

Ryuk has a fairly humanoid appearance. He is extremely slim and has light-gray skin, almost blue-ish in color, with spiky black hair; thin, blue-gray lips; and sharp, pointed teeth. His limbs are abnormally long, and he wears rings on his fingers. He has large, round yellow eyes with bright red irises and retractable feather-like wings on his back that enable him to fly.

Ryuk is different from most Shinigami in that he does not want to simply pass time away in the Shinigami Realm but find something to relieve his boredom, and he is unaffected by the mocking he receives from other Shinigami for it.

Ryuk regards Light as "interesting," specifically due to his experiments and the loopholes he discovers regarding the Death Note's rules and instructions, occasionally discovering abilities of the notebook even Ryuk did not know existed. Though he finds Light interesting, he does not care whether Light lives or dies and does not actively assist him. At times, he withholds important information from Light and only assists him when he has something to gain from it. As his only purpose in dropping the notebook was because he was bored, most of his actions are primarily motivated by wanting to see something interesting, as he sees Light's use of the Death Note and the way humans react to it as truly entertaining. Ryuk is intelligent, but Light's ability to understand his desires easily makes him able to be manipulated.

Ryuk has a great fondness for apples, stating the addiction to be an equivalent of cigarettes and alcohol for humans. Shinigami apples are withered and taste like sand, as he shows Misa at one point, which is why he prefers apples from the human world. He suffers certain symptoms of withdrawal if he goes too long without eating them, involving twisting himself up like a pretzel and doing handstands. He also states that he is shy around girls, revealed when Misa regains her memories and hugs Ryuk in excitement.

Ryuk is fond of video games, first shown in the omake eight-panel comic series, where he asks Light for a Silver Game Boy Advance SP for Christmas. 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 microphones and rigged with cameras.

While appearing as your typical black notebook, Shinigami are able to choose what adorns their notebooks' covers, if anything. Most notes, however, such as Rem's, are plain black and lack writing on their covers, but Shinigami occasionally write their name on it as a joke. Death Notes can also be red or white, though these types are rare.

Depending on the era, Death Notes change their appearance to match said era. They will be a scroll in Old Japan or appear similar to the Old Testament in medieval Europe.[2] The inside of a Death Note looks like that of a school notebook and contains ruled white pages. The notebook is activated when a human's name is written in it. Regardless of how many names are written in it, the notebook will never run out of pages. Death Notes are made from a material unknown to human science; however, they nevertheless feel and look like regular notebooks, and it is possible to rip and burn the pages.

The purpose of the Death Note is to take human life, thereby increasing the lifespan of the Shinigami who uses it. There are many rules governing how the Death Note can be used, though the most pivotal rule is that "the human whose name is written in this note shall die." The King of Death is apparently the one that makes and controls the rules of the Death Note, where he is able to make new rules as he sees fit.