The Unknown Shinigami first appeared in the director's cut in the one-shot special that only aired in Japan. He appears to be looking for Ryuk as he always appears to be bored of the Shinigami Realm. He asks other Shinigami where he could find him, once he finds Ryuk he bribes him with an apple in exchange for information on how he could reach the Human World. Ryuk accepts his offer and tells him a story of a man that changed the world - Light Yagami - and the legend that unfolded after he found the Death Note. However, before Ryuk can finish the story the Unnamed Shinigami leaves with his eyes fxed on getting to the Human World. The Shinigami has a skelical appearance and wears a dark coloured coat, googles, and uses a tie as a headband. On his back also appears to be a large object that he uses as a hammer.
The Shinigami has been under constant speculation that he is Light Yagami, and due to thirteen peices of evidence;
Another reasoning behind this speculation is the fact that when Ryuk is explaining the Death Note to Light he says; "Do not assume the user of the Death Note can go to neither Heaven or Hell" so the user will go to Purgatory which could mean the Shinigami Realm. This provides a logical explanation to all those whom have used the Death Note, Purgatory (Mu) is neither good or evil (which could also relate to Light's "warped" sense of Justice in from L's perspective and Vice Vera), and living in the Shinigami Realm has been described as living an empty existence, an existence of nothingness amidst a grey and grungy environment.