Though born without a Quirk, he manages to catch the attention of the legendary hero All Might and has since become his close pupil and a student at U.A. High School, making him the ninth user of the Quirk One For All.
Izuku has green eyes, messy, dark green hair with black highlights and four symmetrical freckles underneath both cheeks. During his Junior High School days, he wore a black gakuran uniform with yellow buttons. In U.A., he wears the standard male uniform: a light grey suit over a white dress shirt and dark green dress pants, along with a red necktie that he does not tie properly, making it shorter than it should be. Izuku usually wears oversized red shoes.
Though he was initially very skinny, Izuku has gained an array of well-developed muscles after his ten months of extensive training with All Might. Izuku is often described as being very plain looking.
Izuku's first Hero Costume was a green full-body unitard with a red belt, elbow pads, knee pads, gloves, and red boots. He also wore a mask with long ear-like protrusions that resembled All Might's haircut, and a mask with a smile on it. The costume was severely damaged after Izuku's mock battle with Katsuki Bakugo and had to be repaired.
During the USJ Arc, while his costume was being repaired, Izuku wore his gym clothes: a blue tracksuit with thick white lines over his upper body and legs, which form the letters "UA".
Izuku's second Hero Costume has a few changes, and though some of the original aspects were brought over, it now looks sturdier and more combat-efficient in appearance. His second costume is a dark green full-body unitard with the same red boots and elbow pads. The knee pads have been extended to his legs and reach up to his thighs. His mask with the long ear-like protrusions have been shortened and his hair is shown in the back of the mask. His gloves have blue stripes on them. His mask is now metal, diamond-shaped, and has two holes on the top and bottom, left to right.
During the Hero License Arc, Izuku had his costume upgraded to suit his Shoot Style by adding iron soles to his red boots and extending his gloves and added arm braces to them to keep his arms from breaking and making further damage. His knee pads have yellow bolts in them.
After his fight with Shoto Todoroki, the fingers on his right hand became a little deformed, and he gained two scars on the sides of his hand. His right arm is further damaged after his fight with Muscular, leaving various scars throughout it.
Izuku is a very timid, helpful and polite boy, frequently overreacting to abnormal situations with exaggerated expressions. Due to being bullied since childhood for being born without a Quirk, he is initially portrayed as insecure, being more reserved and not self-expressive, especially in front of Katsuki Bakugo, who constantly subdued him for his aspirations to be a hero. However, after being accepted into U.A. High School, making new friends and facing Katsuki during the Battle Trial Arc, he has gradually turned into a more confident and brave person, to the point of developing some leadership skills.
Izuku is also very diligent and strong-willed. His dream of becoming a Hero drove him to develop a habit of writing down notes about everything he knows in regards to their Quirks. Because of this practice, Izuku has developed a great analytical mind and is easily able to form complex battle plans in a matter of seconds, taking advantage of his allies' and enemies’ Quirks to put them in motion. Izuku externalizes his observations through endless mumbling, a habit which annoys or scares his peers. Izuku often writes down his observations in a notebook he refers to as Hero Analysis for the Future.
Izuku is a caring person, and will never hesitate to rescue someone in danger, even if he knows that he is not strong enough to do it. Often, he does this on a whim, taking a more careless approach than the usual overthinking he goes through. Izuku has also shown to be selfless enough to try to help people with personal, emotional problems, even if it does not concern him, claiming that a Hero is someone that meddles on the lives of other people. Izuku's heroic spirit is recognized by many, having earned the loyalty and gratitude of characters that were previously antagonistic to him such as Tenya Iida, Shoto Todoroki, and Kouta Izumi.
Of all Heroes, the Symbol of Peace All Might is the one that has had the most impact in his life, with the formerly Number One Hero having shaped most of the goals and beliefs that Izuku follows since childhood. Many of Izuku's decisions and actions are inspired by his desire to become a Hero similar to All Might, and thus he has a great devotion for him, to the point of collecting several pieces of various Merchandise related to the Hero and emulating several of his traits. Having inherited his Quirk, one of Izuku's current priorities is to be able to live up to his idol's legacy, as he is always looking for ways to improve his usage of One For All, being aware of the immense pressure that is succeeding the greatest Hero of all time.
Izuku appears to have a more brash and abrasive side to him that mostly shows up when he finds himself in combat. This side of him makes him act more like Katsuki, being rather loud and unwavering, and also with a strong drive towards victory. He claims that this is because he sees Katsuki as the embodiment of what someone who strives for victory should be. He also has admitted that he doesn't like this side of him very much, and tends to keep it in check.
Quirk and Abilities
One For All (ワン・フォー・オール Wan Fō Ōru?): Inherited from Toshinori Yagi, Izuku's Quirk gives him access to stockpiled power, granting him superhuman strength and greatly enhanced agility and mobility by spreading his power through his body. Though he has yet to demonstrate superhuman speed, immense reflexes, and durability on the level of All Might, Izuku has shown to be able to properly control a small percentage of One For All's power, using it to enhance his strength, speed, and agility. If Izuku does not spread One For All throughout his body evenly, his body can be immensely damaged from the force of his movements. Izuku has also displayed a type of mental connection to the previous users of One For All.
Recently, Izuku's reflexes and speed have improved with the use of One For All, being able to hold his ground against various incoming attacks during the Provisional License exam. Izuku's control of One For All has improved as his current maximum is 20% of One For All's power while in Full Cowl, at the time of U.A's Cultural Festival.
- Detroit Smash (デトロイトスマッシュ Detoroito Sumasshu?): The same as All Might's move, except Izuku does it in the form of an uppercut.
- Delaware Smash (デラウエアスマッシュ Derauea Sumasshu?): Izuku flicks his finger to create a powerful wind pressure shock wave. Doing this fractures said finger, limiting the time he can use this move without gravely injuring himself up to ten times.
- One For All: Full Cowl (ワン・フォー・オール フルカウル Wan Fō Ōru Furu Kauru?): Through his training with Gran Torino, Izuku was able to unlock this stage of his power and get better control of his Quirk. This technique allows Izuku to activate 20% (previously 5% which was then improved to 8%) of One For All throughout his body, letting the power course and flow through him instead of concentrating it in one location. According to Izuku, this technique gives him greater maneuverability. Activating this technique gives him enhanced strength, speed, mobility and agility. It also prevents him from breaking his bones when attacking.
- 5% Detroit Smash (5 パーセント デトロイトスマッシュ 5 Pāsento Detoroito Sumasshu?): Izuku activates One for All: Full Cowl then jumps into the air and delivers an enhanced downward punch to the opponent. He has also used this move in the form a straightforward punch.
- Delaware Smash Air Force (デラウエアスマッシュエアフォース Deraruea Sumasshu Eafosu?): Izuku uses his upgraded gloves to direct a blast of compressed air against his foe, possessing enough concussive force to stun Gentle while he was in mid-air, giving Izuku an opening to catch up to him.
- One For All: Full Cowl - Shoot Style (ワンフォーオール フルカウル シュートスタイル Wan Fō Ōru Furu Kauru Shūto Sutairu?): While using One For All: Full Cowl, Izuku uses a fighting style that focuses more on kicking. Izuku concentrates One for All: Full Cowl's effects in his torso and legs rather than his arms, allowing him to put out even more power due to the fact that the human leg muscles are naturally stronger than the human arm muscles, granting him enough power and stability and allowing him to step away from the shackles of having to imitate All Might.
- Shoot Style: St. Louis Smash (シュートスタイルセントルイススマッシュ Shūto Sutairu Sento Ruisu Sumasshu?) While using the Shoot Style, Izuku leaps into the air delivers a roundhouse kick against his opponents face. He first used this in his fight with Gentle and was successful in bringing even an empowered Gentle down.
- One For All: Full Cowl - 100% (ワン・フォー・オール フルカウル 100
%Wan Fō Ōru Furu Kauru 100 Pāsento?): Izuku activates One For All to its fullest extent throughout in Full Cowl, granting him a tremendous boost in speed and strength that allowed him to easily overwhelm the likes of Kai Chisaki. This was first used against Chisaki to protect Eri. The power increase seemingly gives him fire-like trails coming from his eyes and light colored hair. He can currently only use it infinitely with no damage done to his body while in physical contact with Eri. Since Eri has the ability to rewind the state of a person's body, any damage done to Izuku's body by using One For All at 100% would continually be undone by Eri's quirk which proved useful in his fight with the villain.
- One For All: Full Cowl - 100% (ワン・フォー・オール フルカウル 100
- One For All 20%: Izuku uses 20% of One for All's full power and distributes it throughout his body, giving him an even greater power and speed boost. While it won't cause his bones to break, it does put immense strain on Izuku's body, causing him great pain to the point that it feels like his bones are on the verge of breaking.
- One For All 100%: A technique that allows Izuku to attack using the full power of One For All throughout his body.
- 100% Detroit Smash (100 パーセント デトロイトスマッシュ 100 Pāsento Detoroito Sumasshu?): This move involves Izuku activating One For All at 100% and then striking his target with a lunging punch.
- 1,000,000% Delaware Detroit Smash (1000000 パーセント デトロイトデラウエアスマッシュ 1000000 Pāsento Derauea Detoroito Sumasshu?): This move involves Izuku activating One For All at 100% during an adrenaline rush and then striking his opponent with a full-swing smack. During the climax of his battle with Muscular, Izuku not only managed to overpower but launch his augmented opponent with enough force to create an impact crater in solid rock with the strike alone.
Overall Abilities: When not using his Quirk, Izuku relies on hand to hand combat and has decent prowess and physical parameters above that of an ordinary student. This was first seen when he not only managed to counter but slam Katsuki Bakugo in their mock battle in training. However, he has better improved his physical capabilities through training, enough to provide valuable assistance during the battle against Stain. During his second battle with Katsuki, Izuku was able to hold his own against Katsuki and was slightly able to fight back. Even though he was still outmatched in strength and speed; Izuku was also able to injure Katsuki, which shows a drastic improvement in Izuku's abilities as in his first battle with Katsuki he was not able to inflict any serious damage at all.
Keen Intellect: Izuku has proven to be exceptionally intelligent on many occasions, displaying both keen observation and analysis as well as adept intuition and resourcefulness. It is usually his intelligence that has helped him more than his Quirk. Izuku is able to formulate strategies that takes advantage of the situation and uses his knowledge to creatively utilize the Quirks of other people to their full potential, such as working together with Tsuyu and Minoru to escape the villains at the flood zone in the USJ. Izuku also has extensive knowledge on Pro Heroes and their Quirks as well. Izuku's intelligence has allowed him to figure out One For All's mechanisms, allowing him to utilize the Quirk more efficiently in a short span of time. Gran Torino even compliments Izuku's intelligence, saying that Izuku is the type of person who thinks before he acts. Izuku's intelligence is so vast that it allowed him to rank fourth in the academic exams, which showed that all of his training doesn't hinder his studies.
High Pain Tolerance: Izuku has shown in many occasions that he is able to handle and bear with a lot of pain, such times are mostly because of the repercussion of over-using his Quirk. However, he can still manage to move his body despite feeling excruciating pain which was seen in his fight with Katsuki.
- Costume Gamma (コスチューム
γKosuchūmu Ganma?): This is an upgrade to Izuku's second costume that Mei Hatsume created following Izuku's decision to change his fighting style, thus creating Shoot Style. The new additions consist of arm braces to support Izuku's arms in order to prevent further damage, and iron armor soles to enhance his kicking power.
- Iron Armor Soles: This is part of the upgrade of Izuku's second costume. Upon receiving a powerful impact, the iron soles responds in kind through a "blowback" motion.
- In the early concept stages, Izuku was known as "Mikumo Akatani". He had a longer and curlier hairdo, with bangs blocking one of his eyes. He was Quirkless in this concept, relying more on makeshift gadgets and luck to deal with obstacles. His hero costume was also slightly more intimidating. However, the author commented that the first thing that came to his mind when he looked at the design he drew was "Get him a goddamn haircut", this made him think up the current design.
- Regarding Izuku's academic life and performance, his U.A. data is as follows.
- Izuku's name contains the kanji for "green" (緑?), "valley" (谷?), "coming out/being from a certain place" (出?) and "long ago" (久?).
- "久" is also homophonous to "nine" (九? usually read as Kyū), which refers to him being the ninth user of One For All.
- "Deku" (デク?) is another reading of his name Izuku (出久?). Written with different kanji, it can mean a wooden figure or puppet, used as an insult for someone who can't do or achieve anything.
- Izuku's nickname, "Deku", was given to him by Katsuki when they were little as an insult.
- Later, Ochaco finds the nickname inspiring and says that "Deku" gives off a feeling of "I can do it" (頑張る でく?), because of its similarity to the word meaning "to be able to do" (できる?), pronounced "dekiru".
- In the FUNimation dub, both Katsuki and Izuku indicate that his nickname is an abbreviation of a different nickname: "Defenseless Izuku", hence Deku.
- It can also be a reference to the Deku race from the The Legend of Zelda franchise, who are seen as weak by many but can hit pretty hard when they first attack.
- Izuku's rankings in the Popularity Polls are as follows:
- Izuku's favorite food is Katsudon, a pork cutlet bowl.
- Izuku was first planned as an adult, as seen in the one-shot My Hero.
- Izuku shares his birthday with Ichigo Kurosaki from Bleach, another Weekly Shōnen Jump series.
- He also shares his birthday with another U.A. Student, that being Mirio Togata.
- Izuku had a similar personality to Akko Kagari from Little Witch Academia.
- Izuku is similar to Gon Freecss from the Hunter × Hunter series.
- They both have black hair with a green outline.
- They both have main abilities that involves enhanced strength.
- (To Toshinori Yagi) "I have to work harder than anyone else to make it! I'll never catch up otherwise...! I want to be like you...! Like you. The strongest hero."
- (To Katsuki Bakugo) "I'm not gonna be your worthless punching bag Deku forever... Kacchan. I'm... I'm the Deku who always does his best!"
- (To Shoto Todoroki) "Just trying to meet expectations! A smiling... dependable... cool hero... That's what I wanna be! That's why I'm giving it everything! For everyone! Your experiences... your determination... I can't even begin to imagine what all that's like... but... If you become number one without giving it your all... Then I don't think you're serious... about denying him everything! That's why I have to win! I have to surpass you!"
- (To Tenya Iida) "I-I've got a lot to say to you, but... That'll have to come later...! Because it's like All Might said... giving help that's not asked for... is what makes a true hero!"
- (To Toshinori Yagi) "I'll do my best! Whatever you say, All Might... I'll step up to the challenge! As long as you're by my side, I can do anything... That's how I feel, anyway!"
- (To Kouta Izumi) "If all the villains attacking tonight are on his level... everyone's in trouble. And they might be after us students. I need to tell Aizawa-sensei and the Pussycats what I know. If my actions can save any of them... Then I've gotta do something."