Tobi
Tobi (トビ?), whose real name is Obito Uchiha (うちはオビト, Uchiha Obito?), is the leader Akatsuki who was originally Kakashi Hatake's teammate who gave him his Sharingan before his presumed death in the Third Great Ninja War. In reality, he was saved by Madara Uchiha who eventually took him as his apprentice to continue his work after he died. Obito then takes the name of Tobi, a carefree member of the group. After his partner Deidara dies in a suicidal bid to kill Sasuke Uchiha, Tobi starts taking a special interest in Sasuke's development up to Itachi Uchiha's death while leading the Akatsuki. Tobi uses his right Sharingan to use another dimension to make his body intangible as well as teleport over great distances. He is responsible for unsealing Kurama, the nine-tailed fox, from its previous host Kushina Uzumaki to attack Konoha before the series' start, resulting in the sacrifice from the Fourth Hokage Minato Namikaze, who resealed Kurama in his son Naruto.
After Nagato's death, Tobi reveals the Eye of the Moon Plan to the Kage to become host to a resurrected Ten-Tails to cast an eternal illusion called the Infinite Tsukuyomi (無限月読, Mugen Tsukuyomi?), bringing all life under his command. After the Kage refuse to surrender to him, Tobi declares the Fourth Great Ninja War. Kabuto Yakushi blackmails him to form a reluctant alliance. Tobi retrieves Nagato's Rinnegan, replacing his left Sharingan, and uses it reanimate the corpses of the captured Jinchuriki to use the captured Tailed Beasts' power through them. During the ensuing war, Madara is revived and Tobi true identity as Obito is exposed.
Tobi was Kishimoto's favorite Akatsuki character at the time to draw, due to his simple mask. In the Japanese anime, Obito is voiced by Naoya Uchida while his Tobi persona is voiced by Wataru Takagi. In his youth, he is voiced by Sōsuke Komori. In the English anime, Obito is voiced by Neil Kaplan with Michael Yurchak voicing his Tobi persona. Nolan North does Obito's voice in the video games while his younger self is voiced by Vic Mignogna.
Read more about this topic: List Of Naruto Characters, Antagonists, Akatsuki