Ryuk's Death Note

Ryuk's Death Note is the Death Note owned by Ryuk. No character except Ryuk himself has touched or used this Death Note.

Plot
When he first meets Light Yagami, Ryuk warns him that when it is Light's time to die, Ryuk will write his name in his own Death Note.

When Light is about to die in the manga, Light begs him to write the names of the Japanese Task Force and SPK members down in his Death Note. Agreeing to write down a name, Ryuk pulls out his Death Note, but instead, unimpressed with Light's "pathetic" display, Ryuk writes down Light's name instead.