The five most powerful countries in the Naruto world are allowed to call their leaders Kages. The leaders are titled as follows:
Hashirama Senju (The First Hokage)
One of the founders of the Leaf, Hashirama Senju helped establish the ideal of all the Hokage who followed. He was originally the leader of a very powerful clan, the Senju clan. It was with a peace pact with their rivals, the Uchiha clan, that Konoha was created. The villagers selected Hashirama as their leader instead of Madara, leader of the Uchiha. This caused Madara to flee the village and challenge Hashirama. After a fierce battle, Hashirama defeated Madara Uchiha and took the leadership role in Konoha. Due to Madara summoning the Nine-Tailed Demon fox, Hashirama was forced to seal it inside of his wife, making her the first Nine-Tailed Jinchuuriki.
Tobirama Senju (The Second Hokage)
As a member of the Senju clan and the younger brother of the first Hokage, he helped build up Konoha. Tobirama founded the ninja academy, the Anbu, the Chuunin exams, and the Konoha Military Police force, which was created to limit the growth of the Uchiha. He excelled in water release techniques, having a mastery of the manipulation of water that is dominant to all shinobi before and after him. He wields the Sword of the Thunder God, a sword that exerts lethal electrical charges. One time, his team was locked in a deadly battle. They were fighting 20 elite ninja. Tobirama sacrificed his life to allow his team to get away, reinforcing the values of the title of Hokage.
Hiruzen Sarutobi (The Third Hokage)
He was the teacher of Orochimaru, Jiraiya, and Tsunade. Due to Madara attempting to release and control the beast inside of Minato (The Fourth Hokage's) wife and Minato sealing the fox within Naruto Uzumaki, Hiruzen was forced to resume the role of Hokage after the fourth sealed himeself inside of Naruto.. He was one of the elders involved in the massacre of the Uchiha clan, though he was the only one who was against it. As a result, he promised Itachi that he would keep Sasuke safe. Hiruzen is known for using an extremely wide range of jutsu of all types. His taijutsu uses the Enma pole, delivering a powerful combination of deadly strikes and blows. He was the only Hokage able to summon the Enma, a monkey. Enma could turn into a diamond hard staff which could alter its length and width at will, or a cage to protect him.
Minato Namikaze (The Fourth Hokage)
Also known as Konoha's Yellow Flash, he is the father of Naruto Uzumaki and the husband of Kushina Uzumaki. He was the student of Jiraiya and the teacher of Kakashi, Obito Uchiha, and Rin. In a heroic battle against Madara Uchiha and the Nine-Tailed Fox, Minato released the Nine-Tailed Fox from Madara's control with a curse seal, applied a seal to Madara so that he can teleport to him whenever he wanted, saved Naruto and Kushina from Madara, and sealed the bijuu within Naruto, making him it's next jinchuriki. Minato is able to use the Flying Thunder God Techinique, which permits him to teleport to any location. He can teleport other beings, as he teleported the Nine-Tails away from the village. He was also capable of making space-time barriers, as he did when the Nine-Tailed fox attacked the village. Minato appeared to Naruto when he was about to relase the Nine-Tailed fox. Minato and Naruto talked about Pain, and about how he is likely being controlled by Madara. After restoring the seal on Naruto's stomach, he told Naruto that he believed he would find a way to stop the vicious cycle of war.
Tsunade (The Fifth Hokage)
Recognized as one of the Legendary Sannin of Konoha, she took the position of Hokage once her teacher the Third Hokage died. She took Shizune, her dead lovers niece, as her apprentice. She owns a pet, a pig name Tonton which she leaves in Shizune's care. Tsunade has many abilities, some of them being unique. Tsunade can convert her chakra into electricity. With a quick strike behind an opponent's neck she is capable of sending electric waves into the opponent's nervous system. This then scrambles the electric signals within them and disrupts the way their body moves, such as attempting to move the right hand would cause the left leg to move instead, and so on. Tsunade is known for her incredible strength. She is able to send her opponents several meters with a mere flick, and cause giant craters with a punch. Her legendary strength is amplified even further with chakra control to monstrous levels. By storing chakra and releasing it, she can lift inhuman amounts of weight, as seen from her lifting Gamabunta's gigantic sword several meters into the air and slam it down through the roof of Manda's (Orochimaru's Snake) mouth. Tsunade uses a transformation jutsu to make herself appear as if she was twenty. When her chakra runs out, this jutsu wears off and she reverts back to her regular appearance. She is considered to be the most skilled ninja in medical ninjutsu. Her most powerful jutsu is her Creation Rebirth, which makes her heal at such a rapid rate that she is invincible in battle. Finally, Tsunade is able to summon slugs, including Katsuyu. She has a mental connection with Katsuyu and is able to send mental messages. With her slugs, she can heal multiple people as she did when Pein attacked Kanoha.
Danzo Shimura (The Sixth Hokage)[temporary]
Danzo was one of the elders who suspected the Uchiha clan for releasing the fox, and therefore supported putting them in a small area of the village so they would be easy to monitor. He took Shisui Uchiha's arm and Sharingan and implanted them onto his own body. He also worked with Orochimary to get the first Hokage's DNA into his right arm. This gave him the ability to use 11 sharingan that he stole from Uchihas, with the additional effect of allowing Danzo to use Wood Release ninjutsu and ultimately the forbidden dojutsu Izanagi. Finally, he had the ability to summon Baku, known as the "Dream Eater", which had the ability to suck in objects in front of it. He founded a section of the Anbu named "Root", of which Sai is a part of, and secretly controlled it to serve his needs.
The First Kazekage
He was the founder of the Hidden Sand Village, athering the desert-dwelling shinobi under his control with his overwhelming power. He wore a mask that covered the lower half of his face. Not much else is known about him.
The Second Kazekage
The first to research jinchuriki, not much else is known about this Kazekage.
The Third Kazekage
He had the unique ability to manipulate his chakra and convert it into magnetic forces, which made him immune to all metallic weapons. After studying the host of Shukaku of the time, he recreated its sand-manipulating powers by combining his own magnetic chakra and iron powder, which produced the Iron Sand technique. It was for this very ability that he was noted as the strongest Kazekage in the entire history of the Hidden Sand Village. Sasori killed this Kazekage and made him his puppet. In Sasori's battle against Chiyo and Sakura, the puppet was destroyed.
The Fourth Kazekage
As Gaara, Temari, and Kankuro's father, he was a cruel leader. He ordered Chiyo to seal the One-Tailed Shukaku into his son, Gaara, so that he may become a weapon for the village. After he realized that the powers have begun to manifest themselves in Gaara, and realizing Gaara's desire for independence and unruliness, he ordered that Gaara be assassinated. All attempts at killing Gaara by the Fourth Hokage were unsuccessful. He teamed up with Orochimaru to infiltrate the Hidden Sand Village with Gaara, planning on releasing the Shukaku during the Chunin exams and having the other sand ninja attack from within. Orochimaru betrayed the fourth and killed him and all of his guards.
Gaara (The Fifth Kazekage)
He is the brother of Temari and Kankuro and is the host of the One-Tailed Shukaku. Primarily, he was ruthless and murderous, which changed due to Naruto. Now, he remains hostile toward his enemies but very protective of his friends and innocents. He showed this during his battle with Deidara, and during the meeting of the Kages when he stepped up against the Raikage to protect Sasuke. He believes that all of the villages must cooperate in order to defeat the Akatsuki. Gaara has many sand-based ablities. His fighting style is stationary, and he usually uses a catch-and-crush strategy. He captures the opponents in a sand coffin, and crushes them with varying intensities. Even since the Shukaku has been removed, he is still able to control sand and use all of his defensive sand moves.
Yagura (The Fourth Mizukage)
During his reign, the village was known as the The Village of the Bloody Mist. This was because he would have academy students kill each other in order to graduate, which eventually gave birth to a murderous Zabuza Momochi. Ao, a character with a byakugan, confirmed that Yagura was being controlled by Madara Uchiha. After his mysterious death, he was later revived by Kabuto to fight in the Fourth Great Shinobi War.
Mei Terumi (The Fifth Mizukage)
Mei is a cheerful person who is almost always smiling regardless of what she is saying, such as when promising to kill someone. Mei is capable of using Earth, Wind, and Fire natures and has two Kekkai Genkai. The first, by fusing earth and fire elements, allows her to use lava release ninjutsu, such as spitting out lava. The second, by fusing water and fire elements, allows her to use boil release ninjutsu, such as releasing a corrosive mist that can burn away anything it touches. It even managed to burn through Sasuke's Susanoo.
The Third Raikage
The Kage responsible for capturing the Eight-Tailed Giant Ox and sealing it within Killer Bee, his only known skill is in fuinjutsu, as he sealed the Eight-Tailed Giant Ox in a pot once it was restrained.
The Fourth Raikage
He is the older brother of Killer Bee, the jinchuriki of the Eight-Tailed Giant Ox. He recently attained the title of the supreme leader of the Shinobi alliance. With a chakra level comparable to a tailed-beast, he fights with a signature nintaijutsu style of fighting. He was able to break through Sasuke's amaterasu covered Susanoo bones. He uses a lightning technique in battle, and also to speed himself up and be so fast that even the Sharingan has difficulty keeping up with him.