Minato Namikaze

Minato Namikaze, also known as Konoha's Yellow Flash was the Fourth Hokage, and the father of Naruto Uzumaki.

Early life
According to those who knew him, Minato was a very talented ninja-having graduated from the Academy at the age of ten. He came under the tutelage of Jiraiya, and under his guidance, learned to develop his skills. Impressed with Minato's determination to succeed, Jiraiya took it upon himself to teach the latter the technique of frog summoning. Minato mastered the technique, being the only person to fully control Gamabunta, a feat not even his sensei could outdo. His skills would further grow with the development of his own variation of jutsu—Rasengan and Flying Thunder God Technique.

After attaining the rank of Jonin, Minato was given direction of his own team, which consisted of Kakashi Hatake, Rin and Obito Uchiha. Along with Kakashi, Minato's reputation greatly increased during the Third Great Ninja War, where his skills earned him the moniker of Kohona's Yellow Flash. As a gift for Kakashi's advancement to Jonin, Minato gave him a unique kunai marked with one of the Hiraishin transportation markers. Shortly afterwards, he informed the team of their mission: destroy a bridge that aided the enemy Rock ninja force. For the mission, Kakashi took Minato's place as commander of the team. However, before the group was able to complete their mission, differences between Obito and Kakashi lead the team to be caught in a trap. Using the transportation technique, he was able to wipe out all 50 rock ninja with little trouble. After this battle, Rin used Kakashi's kunai to bring Minato to her location to protect her and an unconscious Kakashi from Rock ninja. Unfortunately, by the time he arrived Obito was already dead, though he managed to save Kakashi and Rin. They would later go on to fulfill their mission and help repel the Rock invasion.

Fourth Hokage
In the months to come, Minato was chosen by the Third Hokage to lead as the village's new leader. His first choice, Orochimaru, failed to live up to his expectations-though he thought Minato to be a fine replacement. His devotion to the village and his love for his friends inspired all those around him, and as such, Namikaze became well-liked by the villagers. It was during this time that Minato started a family of his own, and fathered a son, Naruto, with Kushina Uzumaki, a kunoichi from the former Whirlpool Country. However, just moments after Naruto's birth, the Nine-Tailed Demon Fox attacked Konoha. Minato rushed to the village, where he and Gamabunta faced off against the Tailed beast. Near the end of the battle, Minato made the ultimate sacrifice; using the Dead Demon Consuming Seal, he sealed the demon fox into his newborn son, in exchange for his own life. His dying wish was that Naruto be viewed as hero, and not as the container of the demon fox, a request not honored by the villagers.

Legacy
When sealing the demon fox, Minato divided the fox's chakra in two halves as he sealed the beast into Naruto. He sealed the Yin chakra with the Dead Demon Consuming Seal making it inaccessible to Naruto, while using the Eight Trigrams Sealing Style and the Four Symbols Seal on the Yang chakra to give Naruto access to it. This way, Naruto could call upon the demon fox's chakra without being completely controlled by it, though the Four-Tailed Transformation seems to negate this effect. Jiraiya states Minato wanted Naruto to have the Seal Key that matched Naruto's Trigram Seal to help complete a yet to be identified technique.

Personality
Although unknown, Jiraiya and Tsunade point out that, while Naruto physically bears great resemblance to the Fourth, his personality and style of ninjutsu are almost identical to his mother. This and an earlier statement from Jiraiya on the mission to retrieve Tsunade imply that Naruto and Minato had rather different personalities. Jiraiya notes that, although he was quite a genius, the Fourth's greatest aspect was his desire to succeed, largely attributing his success to hard work.

Abilities
The Fourth created several distinctive techniques, including the Flying Thunder God Technique, which essentially allowed him to teleport to any location with the use of a special seal. He also created the Rasengan, a technique that does not rely on hand seals, but instead uses a concentration of spinning chakra in the palm that causes immense damage to its victim on contact. Later in the series it is revealed that this signature technique is actually incomplete. The Fourth had planned to add his own nature manipulation training to the Rasengan, making it even more powerful, but couldn't manage to combine the two prior to his premature death.

Past Speculation
Before it was revealed, many people believed that the Fourth was Naruto's father because of the many similarities they shared. For example, they both had the same spiky blond hair, blue eyes, techniques, blood type, and overall similar personalities as noted by Jiraiya. Itachi Uchiha noted Naruto to be the Fourth's "legacy". Also, when Jiraiya was trying to force Naruto to release his demon fox chakra, he pushed Naruto off of a cliff, saying, "Forgive me, Fourth," as he did so. Beyond these, there are several minor comparisons made consistently thought the series. Any hints to his name, history, or family relations have been carefully avoided, making his past one of the biggest mysteries of the series until it was finally revealed in Chapter 367.

Trivia

 * According to Jiraiya, the Fourth is the most skilled Leaf shinobi ever to live.