Ryuk

Ryuk (リューク, Ryūku) is a Shinigami who, after becoming bored with the Shinigami Realm, steals a second Death Note and drops it into the Human World. This Death Note is discovered by Light Yagami who uses it in an attempt to cleanse the world of evil and injustice. This leads to Light's conflict with L, Near and Mello, thus satisfying Ryuk's need for entertainment.