Iruka Umino

is a chūnin-level shinobi of Konohagakure that primarily serves as an instructor at the Academy.

Background
Iruka's parents were killed twelve years before the start of the series, defending Konoha from the Nine-Tailed Demon Fox. Initially, he was present on the battlefield, telling his father he wouldn't leave, but stay and protect his mother. His father shouted at him that it was the parents' duty to protect the child. He was later forcibly removed from the battlefield by an unknown shinobi.

With his family gone, Iruka had no one to give him attention. Iruka thereafter became a prankster much like Naruto would later become, trying to gain attention to stave off his loneliness. He would spend his time at the monument where his parents' names were engraved, and, in his darkest moments would be cheered up by the Third Hokage. Mizuki was a childhood friend of Iruka's after the Nine-Tails Attack, and usually made him feel better. It later turns out, due to other people giving Iruka more attention than they do to Mizuki, Mizuki's kindness to Iruka revealed to be an act just to gain the Hokage's approval, all the while making Iruka miserable discreetly.

In a non-canon filler, Iruka was shown to have become a teacher because he wanted to pass on the Will of Fire to the next generation, inspired by the Third Hokage's wisdom. When Naruto became his student, he found it awkward to deal with the very monster responsible for his parents' death. He tried to ask the Third Hokage if he could not teach Naruto, though he was eventually disabused by the notion by his former mission commander, Kakashi Hatake. Later, Naruto went into the woods to steal items from corpses. Iruka chased him down and protected him from Takigakure spies who were attacking Naruto, eventually backed up by Kakashi. After saving Naruto and bringing back the document attached to the artifact the latter retrieved, he thanked the Third for assigning Naruto to him. He thus resolved to be straight forward and deal with Naruto strictly in class from then on, in order to train him to become a fine shinobi.

Personality
Although he owes much of his miserable childhood to the Nine-Tails, he has no hostility towards its container, Naruto Uzumaki, and even cares for him as family. Early on in the series, he relates to Naruto's efforts to win the recognition of others through his antics; a tactic that he also used in his childhood to cope with his feelings of loneliness, which he can sense in Naruto.

Because of this, Iruka goes out of his way to connect with Naruto outside the classroom — having realised that he could do more good as a mentor, than as a teacher. Iruka becomes even more aware of Naruto's situation when the Third Hokage asks him to contemplate living among people who would deny his very right to exist. Likely due to Iruka's more nurturing and compassionate nature, Naruto views him as a mentor and Iruka in turn, views Naruto as a younger brother. The two enjoy their favourite ramen dish at the Ramen Ichiraku whenever Naruto returns from a mission, where Iruka gets an opportunity to see how Naruto is developing as a ninja. Iruka's refusal to allow Naruto to graduate at first was not out of spite, but merely out of caring strictness and a desire for Naruto to work harder and reach his own potential.

Having known both loss and loneliness, he is sympathetic to others and instinctively tries to console others in times of grief or loss. Iruka is often the first person Naruto turns to when trying to understand issues of selflessness and honour. Iruka greatly admires both the Third Hokage and his beliefs. As a result, he regards the children of the village as the backbone of Konoha — even being willing to sacrifice his own life to ensure their safety.

Appearance
Iruka has black hair (brown in the anime) that he keeps in a ponytail, dark eyes and a scar across the bridge of his nose which he has had since his youth. He wears the standard Konoha shinobi outfit complete with forehead protector, sandals and flak jacket.

Abilities
Little is known about Iruka's abilities. As a head instructor of the Academy, he is clearly proficient in all forms of basic ninja skills. He has some ability with Barrier Ninjutsu after using one in an attempt to restrain Naruto. Iruka is also very perceptive as he is able to assess situations carefully and quickly while under threat.

In the anime, Iruka skills were expanded upon and it was shown that he had some knowledge of genjutsu, as demonstrated when he posed as an enemy Amegakure ninja to test Sakura, and he also saw through the genjutsu cast by Mizuki. During the Mizuki Strikes Back Arc, Iruka showed some skill in taijutsu as well, by keeping on equal footing with the now-improved Mizuki in his attacks. Iruka was also shown using Sealed Bomb Square Release, which consists of setting an array of exploding tags and, once the target has entered the area, setting the tags to detonate if the target moves.

Also, in the anime, Iruka is given what seems to be an echolocation ability where he can get a sonar image of his surrounding area, perhaps playing on the meaning of his name, "dolphin".

Introduction Arc
When Naruto was desecrating the Hokage Monument with graffiti, Iruka yelled at him to get down and tied him up, berating him to focus on the upcoming graduating exams. While Naruto was supposed to transform into Iruka, he instead turned into a naked girl, which caused Iruka's nose to explode with blood, and earned Naruto a reprimanding. Iruka then punished Naruto to clean the Hokage Monument, but then invited him to Ramen Ichiraku, where he learned of Naruto's desire to be Hokage.

Next day, when Naruto failed to perform three clones, Iruka failed him from graduating, ignoring Mizuki's false sympathetic request. Later, when Mizuki tricked Naruto into stealing the Scroll of Seals, Iruka came to his aid. Iruka protected Naruto from Mizuki's attacks and, after Naruto found out about the Nine-Tails within him, insisted that he didn't hate him. After the ordeal, he allowed Naruto to graduate from the Academy, due to the genin's newly acquired ability to create a high amount of advanced clones. From that point further, he makes sporadic appearances.

Chūnin Exam Arc
He voiced concern about Team 7 being entered in the Chūnin Exams, such that, in the anime, he personally tested each member individually to see if they were ready by disguising himself as a Amegakure ninja. Once they passed the exam's second phase, he acted as a messenger that granted them access to the preliminaries.

Invasion of Konoha Arc
During the invasion of Konoha, Iruka escorted his students to safety in the shelters behind the Hokage Monument- promising that he and the other instructors would protect them "even at the cost of our lives". He shared ominous looks with Konohamaru when the Third Hokage's representation cracked, and he comforted Konohamaru during the Third's funeral.

Search for Tsunade Arc
He met Naruto at their favourite Ramen Ichiraku to listen to Naruto talk about his adventure and later explained to Naruto that they have to do many missions to show other villages that they were still strong, even though their strength had been cut in half.

Mizuki Strikes Back Arc
In the aftermath, Iruka was forced to suspend his teaching duties in order to go on missions and fill the void in personnel. In the anime, he was assisted by Pakkun to find Mizuki and go after Naruto and Tonton. When Iruka caught up, they send Tonton back to the village and Pakkun leads Naruto and Iruka to Shizune. Shizune led them in pursuing Mizuki, when they soon fell into a trap. Iruka then revealed that Shizune is not Shizune but Mizuki himself. While Naruto battles with Fūjin and Raijin, Iruka battles it out with Mizuki. Iruka wanted to bring the "old" Mizuki back, but Mizuki revealed that he was only nice to Iruka because he is the Third Hokage's favourite. Mizuki led Iruka into a building used to test Academy instructors and battled there. After that, Naruto and Pakkun caught up with Iruka and they went to Mizuki's lover, Tsubaki. Tsubaki helped them reach Mizuki but it was too late. Mizuki had drank a formula and became stronger and monstrous. They battled again with Mizuki having the upper edge. Iruka came up with a plan to trap Mizuki, giving Naruto a chance to use Rasengan on Mizuki.

Ultimate Weapon Arc
He later found time at the end of Part I to see Naruto off before he left the village to train with Jiraiya.

Kazekage Rescue Arc
Iruka met with Naruto when he returned two and a half years later, and cheered him up after he found out that all of his friends had advanced in rank during his absence.

Invasion of Pain Arc
After Jiraiya was killed, Iruka comforted Naruto, and told him that Jiraiya would always be proud of him. He went on to inform Naruto of how Jiraiya had always bragged about him, and had mentioned multiple times how he thought of Naruto as a grandson. Iruka also reminded him that he was now the one to carry on Jiraiya's legacy. During Pain's attack on Konoha, Iruka was found by one of Pain's bodies while attending to a wounded ninja. He refused to tell Pain where Naruto was, and was almost killed. Kakashi intervened, however, allowing Iruka a chance to get the ninja to the hospital and to later join a squad of Konoha ninja to help repel the invasion.

Following Pain's attack, Iruka was last seen apparently injured but alive, having been protected by one of Katsuyu's divisions. After Pain resurrected everyone he had killed, Iruka was seen standing along with the rest of the villagers. He thought back to the days when Naruto was at the academy, and compared it to the present while watching Naruto being cheered at by the whole village. After these memories, a proud smile spread across his face.

Konoha History Arc
In the anime, Iruka was later seen meeting with his fellow teachers Suzume and Daikoku Funeno making preparations to salvage items for class. He sees the Academy and remembers being appointed by the Third Hokage to be Naruto's teacher.

Shinobi World War Arc
During the Fourth Shinobi World War, Naruto and Killer B, as the last two Jinchuriki, were confined to an island to keep them out of Akatsuki's clutches, (Naruto being unaware of this, and the war). After Naruto began to get suspicious and tried to leave, a handful of shinobi tried to stop and convince him to go back in. Iruka was among them, and he convinced Shibi Aburame to let him talk to Naruto. Iruka attempted to trick Naruto into believing he had a second mission on the island. However, Naruto decided to go outside anyway and used Sage Mode to barge through the guards, in the process losing his forehead protector. Before he could leave, however, he was bound by the Shadow Imitation Technique by a Nara clan member, but not before he sensed the war raging outside.

With Naruto demanding the truth, Iruka revealed that there was a war raging in order to protect him, and tried to persuade him not to intervene and risk capture. When Naruto declared that he would end the war on his own, Iruka said that Naruto was like a little brother to him, and he wouldn't be able to bear it if Naruto was captured. Naruto stated that it was Iruka who first recognised him and gave him his forehead protector, and asked him why he was starting to doubt his power now.

Glancing down at Naruto's fallen forehead protector, Iruka decided to return it to him, only to erect a barrier to trap Naruto. Naruto however enters his Nine-Tails Chakra Mode and easily breaks out of the barrier and resisted all attempts to subdue him, before making his way to the battlefield. On his way, Naruto found a note in his forehead protector, from Iruka, telling him to come back alive. When Killer B arrived, Iruka told him to protect Naruto and they bumped fists. The Eight-Tails told him that he couldn't keep an eye on Naruto but B said no one could, and said to Iruka that he was in Naruto's heart and everything he taught was still inside, even today.

Trivia

 * Despite having made very few appearances later on in the series, he has finished in the top five in every poll until the most recent poll.
 * Iruka was one of five characters that have stayed in the Top Ten of every Character Popularity Poll.
 * In the first databook, Iruka's age was given as 25. In the second, it was listed as 23.
 * The name "Umino Iruka" when broken down as "umi no iruka" means "sea dolphin".
 * According to the databook(s):
 * Iruka's hobby is going to the hot springs.
 * Iruka's favourite food is ramen from Ramen Ichiraku, with his least favourite being ; a type of takikomi gohan, but with the ingredients added in various stages while cooking.
 * Iruka wishes to fight Nine-Tailed Demon Fox and his students.
 * Iruka has completed 573 official missions in total: 288 D-rank, 183 C-rank, 90 B-rank, 12 A-rank, 0 S-rank.
 * Iruka's favourite word is.
 * Iruka's scar is similar to the crack across the bridge of the nose of the First Hokage's monument head on the Hokage Mountain.

Quotes

 * (To Naruto) "Master Jiraiya only had praise for you. He was always boasting about you, saying you were like his own grandchild. He had faith that you were the one who would inherit his will, and truly believed that you would one day be a great Hokage. Master Jiraiya will always watch over you. Even this very minute, he's watching from somewhere. He wouldn't be happy seeing you sad like this. So.. Be your usual self, the one he praised so much. Don't stay depressed forever. For Master Jiraiya himself, one of the Legendary Sannin… acknowledged you as his promising student!"
 * (To Naruto) "Stop acting like a baby! You want to know what I really think of you?! I think you're one of my most precious students… and… you're like a little brother to me."
 * (Letter to Naruto) "I expected you'd try to rush out to the battlefield right away. I know you're ready to fight. If you're reading this letter it means I couldn't stop you. Lady Tsunade ordered us to Kumogakure's secret island to guard you and delay you from leaving as long as possible. I'm writing this letter just in case things don't work out like I want them to… which is pretty pathetic considering I'll be on an official mission. But if that's how it goes… I don't know if I'll manage to give this to you or not, but there's something I need to tell you. In fact, now that you've left, it's the only thing left to say. Come back alive, Naruto!"