Throughout all of the Naruto plot, strong emphasis on character development changes the plot, with very few things happening because of chance. At first, emphasis is placed on Naruto, Sasuke, and Sakura, who are the members of Team 7. However, other characters are developed, such as Kakashi, Tsunade, and Jiraiya, as well as Naruto's peers in the other teams and villages. Several major villains come into play as well, the first being Zabuza Momochi, a missing-nin from Kirigakure, and his partner, Haku. Later, in the Chunin Exams arc, Orochimaru, an S-Class missing-nin at the top of Konoha's most wanted list, and his loyal right-hand man, Kabuto Yakushi, are introduced. During this same arc, three ninjas known as the Sand Siblings are introduced. These siblings are from Sunagakure and include Temari, Kankuro, and Gaara. Later still, a mysterious organization called Akatsuki begins to pursue Naruto for the Nine-Tailed Demon Fox that is sealed inside of him.