Ōnoki

is the, and the leader of Iwagakure. He is called. He is apparently the oldest of the current Kage.

Background
At some time in the past, Ōnoki fought with Madara Uchiha, the only living Kage to do so. He has also apparently known Ē, the Fourth Raikage, since the latter was young.

Appearance
Ōnoki is an old man with a size of one and half times his head piece. His facial features include a triangular beard and a mustache with angular corners. He has a big red nose and thick eyebrows (similar to those of Rock Lee). The top of his head is completely bald, although, he has some hair at the back and sides of his head, the back of which is tied with a yellow ribbon into a ponytail. All of his hair (ponytail, sideburns, facial) is white.

Personality
Ōnoki is very proud but appears frail, with constant complaints referring to his hips and back. He also refuses to retire and choose a successor as Tsuchikage despite his frailness, and insisting that he is plenty strong to continue to rule the village. Kurotsuchi describes him as a "stubborn old man." His pride has him give very little respect for those younger than him, as he verbally attacked Gaara, who is many years younger, on numerous occasions. He also seems to be quite ruthless, taking down a heavily-injured Sasuke, who just finished fighting three other Kage before him, on the claim that everyone else there wants Sasuke dead even though Ōnoki himself has no grudge against Sasuke personally, and then immediately turning his attention to a devastated Karin, claiming that she's next to die. He does, however, seem to be considerate enough to let Madara speak for his actions, reasoning with the Raikage to listen to his reasons before their actions first before making their own. According to his thinking of strategy, Onoki might be the type of person who takes risks. A similarity can be shown with Tsunade, as she has a habit of gambling and taking risks often. Remembering what Gaara said to him, he states to Akatsuchi and Kurotsuchi that he remembered what he really used to be before he became a stubborn old man, possibly meaning he had a more kind and friendly heart in his youth.

Five Kage Summit arc
When Ōnoki sets out for the Kage summit, the villagers of Iwagakure encourage him to show the other Kage how strong he is. His escorts, Akatsuchi and Kurotsuchi, are less encouraging; the latter tells him to retire, and the former offers to hold Ōnoki's luggage so he will not over exert himself. He tries to refuse Akatsuchi's offer by carrying his luggage himself, but hurts his back and must be carried.

After they arrive in the Land of Iron and the meeting begins, Ōnoki expresses his concern that Akatsuki could capture the jinchūriki so easily, considering it an embarrassment. When Ē ridicules him for employing Akatsuki in the past, Ōnoki defends Iwagakure's actions and instead blames Kumogakure for increasing its armaments in times of peace. Mifune suggests that the five Kage join forces against Akatsuki, nominating Danzo as the group's leader. Ōnoki is outraged by the suggestion, but Mifune points out that he is too old and has made too much use of Akatsuki in the past to be trustworthy.

When the Kage are alerted to Sasuke Uchiha's presence and the Raikage goes off to confront him, Ōnoki comments that he is just as reckless now as when he was young. Until Ē's return, he offers to give Gaara tips on how to be a good Kage, having previously dismissed Gaara's suggestions on the basis that he is too young. Gaara only asks why he has no faith.

Sasuke soon arrives at their location, but Ōnoki chooses to let Mei Terumī deal with him. After Sasuke proves able to evade her attacks, he decides to intervene, attacking Sasuke with Dust Release: Detachment of the Primitive World Technique, then turning his sights to the devastated Karin. Although Ōnoki believes he has turned Sasuke to dust, Madara Uchiha appears with Sasuke in tow. Madara sends Sasuke away and tells the Kage of his Eye of the Moon Plan. Because Madara concludes by requesting that the two remaining jinchūriki be given to him, Ōnoki and the other Kage refuse, beginning the Fourth Great Shinobi World War.

With war declared, Ōnoki, Gaara, Mifune, Mei, and Ē agree to form a coalition against Madara and Akatsuki. The group does not trust the Hokage, so Ōnoki agrees to seek Konohagakure's assistance by approaching Kakashi Hatake. In terms of tactics for the forthcoming battles, Ōnoki suggests they use their two remaining jinchūriki to their advantage, but the other Kage disagree, believing that would make them too easy to be captured.

After it was decided that Ē would lead the Ninja alliance, he asked Ōnoki to reveal all the knowledge he had on Madara as he once fought him. Later while talking with his men on what actions to take, they are surprised that Ōnoki refuses to take the most logical action merely killing Naruto and Killer Bee so Akatsuki can't get them. When asked why, he merely states because he remembers who he was "Before he became a hard-headed old man", referring back to how Gaara talked down on him about "losing himself".

Abilities
Despite being physically frail, he seems to be both knowledgeable and confident in his ninjutsu skills. Ōnoki's Dust Release ninjutsu allow him to pulverise his enemies to molecule-sized dust. He is also skilled with Earth Release ninjutsu and has shown the ability to levitate.

Quotes

 * (To Akatsuchi)
 * (To Ē) "It's better than losing the war, I suppose... Plus, if the shinobi world ends, where will I fight with you...?"
 * (To Kurotsuchi) "Because I remembered...Who I used to be before I became a hard-headed old man."

Trivia

 * The word "Ryōtenbin" literally means "two alternatives"; this may be why the Viz translation has Ōnoki calling himself, "...the great Fence-Sitter of Iwagakure!"