Shinigami (死神, Shinigami, lit. "god(s) of death" or "death god(s)") are types of Japanese death gods. They are sometimes referred to by their literal translation "god(s) of death," or by the Western equivalent "grim reaper(s)."
In the Death Note series, they are a race of extra-dimensional beings who survive by killing humans to extend their own lives. Shinigami are not responsible for every death that occurs; people will eventually die regardless of whether or not the Shinigami pay attention to them, but a Shinigami can end their lives sooner than intended to extend their own.
Roketto is the king of the Shinigami realm, and for him to leave his throne is a very big deal. As the king of Shinigamis and ruler of the Death Notes, he is able to bend the rules ever so slightly. The Shinigami King rules and governs all Shinigami. He also controls all "distribution" of each and every given to all Shinigami upon their "creation." He creates Death Notes and he is unwilling to replace lost ones. To keep this pressure and responsibility away, he decided to drop his Death Note in the human world, which came into the hands of (Y/N) (L/N); a dangerously charming and beautiful girl who managed to make the King of Death fall for her.
