- “From kindergarten to elementary school, to middle school and high school. The two of us have been together as long as I can remember, and yet... we've never exposed our true feelings and talked things out... not even once.”
- — Izuku Midoriya, Chapter 119.
Izuku and Katsuki have known each other since a very young age, it being noted many times throughout the series that they are childhood friends. Due to a series of misguided instances, their relationship deteriorated and became strained after many complications from their childhood, including Katsuki pushing Izuku away due to his fear of Izuku's spirit. Gradually, however, their friendship is repairing as they both mature and try to resolve their issues - Katsuki even beginning to encourage Izuku to become stronger in recent chapters. Despite their issues, Izuku continues to admire Katsuki for a multitude of things, especially his strength and ability as a hero, stating that Katsuki is his true "image of victory".
Originating from childhood, the pair use nicknames for each other, albeit mainly out of spite on Katsuki's half. Despite his general negativity towards Izuku, Katsuki allows Izuku to call him by the childish nickname "Kacchan", without objection. The suffix "-chan" is considered to be very cutesy and feminine, as it is primarily used to refer to children, close friends, or people with a generally cute appearance, obviously contradicting Katsuki's brash and explosive nature. As shown explicitly throughout the series, especially considering Izuku, if Katsuki has a problem with something or someone he will be the first to make a comment about it; making one question why he has no issue with Izuku using this name for him. One theory is that this nickname is one of the small fragments of the pair's childhood that remains untainted - and so Katsuki holds onto it without posing an argument. The only other instance where "Kacchan" has been used was by Kaminari in chapter 163, seemingly in a teasing way; to which Katsuki disregards entirely and leaves the room to go to bed. Horikoshi, the creator of the series, also refers to Katsuki as the nickname on occasion as seen throughout his sketches, but has not revealed much on its origin or history.
Izuku, on the other hand, receives the nickname "Deku" from Katsuki at a very early point in their relationship, which essentially translates to "someone who is useless", referring to Izuku's Quirkless state. Ironically, this eventually becomes Izuku's Hero Name through suggestion from his friend and classmate Ochako, who puts a positive spin on the name and tells him that it reminds her of the phrase "you can do it!". Katsuki is initially angered at this, internally believing it to be another way of Izuku mocking him, but makes no comment otherwise.
Ever since Izuku failed to develop a Quirk, Katsuki has seen Izuku as someone below him in terms of ability and general worthiness, reinforced when Katsuki developed his own Quirk and was constantly praised by his teachers and classmates for it, whilst Izuku was reprimanded for his lack thereof. Being an easily influenced child at the time, Katsuki noticed this dramatic difference in the way they were both treated, realising that Izuku was essentially a nobody in a world where Quirks so heavily define someone as a person. Holding onto the belief that he was going to be the best, Katsuki continued to view Izuku as nothing but a 'pebble' in his path towards becoming a hero, his intense attachment to victory manifesting itself into somewhat of a superiority complex.
Katsuki bullied Izuku for a number of years after this event, using Izuku as an outlet for his anger towards his strive to become the greatest hero. After finding out that Izuku also wants to enter U.A's hero course, Katsuki becomes aggressive and mocks his choice, stating that he has no chance in becoming a hero and should instead "take a swan dive off the roof". Whilst this was said in an enraged stupor in front of his friends, Izuku still concerns for Katsuki's impulsive actions, stating that he could have gotten into trouble if Izuku actually listened to his tormenting.
On his way home, Izuku sees a crowd surrounding what appears to be another villainous incident, and soon discovers that Katsuki has been captured by the same slime monster that All Might saved him from. As his limbs are constricted and his mouth is covered, he is unable to break free, causing him to stare on wide-eyed in despair. Izuku sees this and rushes forward towards the scene, throwing his backpack and clawing at the slime to no effect, until the monster frees up slightly and allows Katsuki to gasp for air. This then spurs All Might and other onlooking Pro Heroes to intervene, eventually ending up saving the pair of them and defeating the villain. Izuku later says that his feet moved on their own once he saw Katsuki in danger, proving his ability to save efficiently as a hero. Upon their next meeting, instead of Katsuki harassing Izuku as per usual, he instead dismisses him, acknowledging that Izuku's bravery saved his life. Izuku also mentions that ever since this incident, Katsuki never physically harassed him again.
After receiving One for All from All Might, their relationship becomes even more complicated through Katsuki's misunderstandings of the Quirk's origin.
During their first training session, Katsuki felt betrayed when he saw Izuku activating his newfound quirk during the ball throwing portion, believing Izuku had been keeping his quirk a secret since they were children. He had to be restrained by Aizawa as he understandably demanded answers from Izuku. Having promised All Might that he would keep One for All a secret, Izuku had to leave Katsuki in the dark about the situation, unknowingly making Katsuki all the more upset about being supposedly mocked and betrayed by his childhood friend.
Later on, after the Hero vs. Villain fight with All Might, Izuku wakes up to find that Katsuki has left and rushes to find him. Izuku confronts him, assuring that he has never deceived him and spills the fact that his Quirk is a 'borrowed' power, deciding to not mention All Might's involvement just yet. He states that he will however make this borrowed power his own and eventually surpass Katsuki by becoming stronger. This causes Katsuki to cry out in frustration, tears spilling from his cheeks as he yells at Izuku to buck up and train hard as well, determined that he will be number one. This is the first time we see Katsuki open up to Izuku despite their tainted past, and this theme continues under the influence of their now shared secret.
In season 2, episode 37 (Chapters 61-65), Izuku is paired up with Katsuki for their final exam, much to each other's dismay. At the start, Katsuki decides to take the lead and ignore Izuku's suggestions of pairing up and avoiding a fight with All Might, well aware of the true extent of his power. Disregarding the idea of backing down from a fight, Katsuki responds by saying that he'll score higher if he defeats All Might; reinforcing his desire to win. Izuku continues to argue against this, to which Katsuki angrily lashes out and punches him, resulting in Izuku landing backwards. As Katsuki walks away, demanding Izuku to not speak to him, Izuku tries once more to make him reconsider; resulting in them shouting at each other, Izuku angrily yelling that this is why they can never have "normal conversations."
All Might then appears, using a Texas Smash down the main street, causing the pair to be blown away. Acting as the villain, All Might menacingly states that the two should take the exam seriously, causing them to react by attacking haphazardly in any way they can. As the exam relies on teamwork, it goes badly for the two of them as the fight progresses, All Might easily managing to outsmart and attack both students without bother.
After All Might pins Izuku under a fence and delivers a punch to Katsuki's gut, All Might tells Katsuki that he has much room for him to grow as a hero, understanding that he is infuriated by Izuku's sudden immense improvement upon gaining his Quirk. Weakly, Katsuki replies: "If you're saying I have to rely on [Izuku's] help, then I'd rather lose."
As All Might prepares to finish off Katsuki, Izuku breaks away from the fence in anger and punches Katsuki in the face, saying "Don't you say you'd rather lose!" He carries Katsuki away to an alleyway whilst All Might is distracted and admits to himself that he can't come up with a plan to pass the exam. As Katsuki is being carried, his mind repeats the words Izuku said to him, triggering a flashback to when the two when they were younger in which Katsuki is scaring away two older children after they caused trouble with him. Obviously scuffed up from the encounter, he scoffs that "the most amazing hero always wins in the end," as Izuku watches on in awe from behind a tree.
Back in the present day, Katsuki yells at Izuku to put him down, blasting out of his grasp. Annoyed at being reminded by his own words, he blasts the wall next to Izuku's shoulder in a kabedon-esque manner, stating that in order to escape they have to fight All Might.
Katsuki comes up with a plan to use maximum firepower on All Might in order to create distance between them. He firstly runs out of the alleyway and distracts All Might, who is initially unimpressed and believes it to be a sneak attack. Katsuki then cries out to Izuku, yelling for him to "shoot" as Izuku appears behind All Might and points at him with one of Katsuki's gauntlets. He fires the gauntlet at All Might, apologising as he does so, catching him off guard. It appears that the plan had worked, seeing no trace of All Might after the collision, until he reappears unharmed and breaks both of Katsuki's gauntlets.
Another fight ensues, chipping away at Katsuki as his ability weakens through use of his Quirk sparing the gauntlets. At one point, All Might even goes as far as to using New Hampshire Smash directly into Izuku's back, causing him immense pain and emphasizing their struggle at this point in the battle. Katsuki, infuriatingly at terms with their current status in the battle, decides his last option is to throw Izuku towards the exit to gain their win. As All Might attempts to stop Izuku, Katsuki comes in to defend his teammate and blasts All Might, who avoids this attack and drags Katsuki to the ground.
Izuku, aware of Katsuki's state, runs back to rescue him so that they can pass together, successfully delivering an attack to All Might that allows him to sweep an unconscious Katsuki under his arm and aim for the exit. He makes it through and therefore wins them the pass. Although Izuku could have easily gained them the win by making his way there alone, he made the conscious decided to go back for his friend, not wanting to leave him behind.
This fight is one of the first major advances in the pair's relationship. It demonstrates their ability to work as a team, the true impact of Izuku's words on Katsuki, and ultimately foreshadows the possibility of them working as a hero duo in the future.
In season three, Izuku pulls together a quick team after a harrowing fight with Muscular that left both of his arms shattered and furiously pursued the villain Compressor, who was holding onto the compressed forms of both Tokoyami and Katsuki . They rescue Tokoyami but a portal opens up and pulls Katsuki in and Izuku desperately tries to reach him. He falls short with the portal closing and Katsuki's broken words being "Don't come, Deku." Deku falls to the ground and lets out a loud scream of anguish before passing out.
At the hospital, Izuku regains consciousness and begins to cry at how he couldn't reach him in time. Izuku and a few other classmates sneak out to go rescue Bakugou. While they are actually performing the rescue, Izuku seems to understand how Katsuki felt about the situation and was able to construct a plan that worked perfectly.
The episode "Deku Vs. Kacchan 2" revolves around Katsuki confronting Izuku about his quirk and how he got it from All Might. He then attempts to fight Izuku, who refused to resort to violence until he sees that he's "the only one who can accept Kacchan's feelings". During the battle, Izuku becomes aware of how Katsuki has felt all this time when he sees Katsuki cry and screaming out his feelings and the burden he had been holding, how he saw Izuku looking down on him and exposing how weak he truly was. To Izuku It's 'the first time the two have had an honest conversation' in a long time. The battle also included flashbacks to when the pair were younger, giving the viewer an understanding of their relationship in the past. The two battle for the rest of the episode, ending in Katsuki's victory and All Might interfering afterwards. He tells Katsuki about the origins of one for all and his successor is Izuku and Katsuki promises to stay quiet. This becomes a secret the three of them share. All Might proclaims that the two have now become proper rivals after they've sorted out their feelings. Katsuki even gives advice to Izuku after he asks how his shoot style was. The bond between them slowly rekindling.
As children, Izuku and Katsuki are seen sharing an intense interest in Pro Heroes, especially in All Might himself, as they both see him to be a role-model in the way he both wins against villains (in Katsuki's case) and rescues those in need (as for Izuku), all whilst doing it with a smile. These divided characteristics are what All Might tells Izuku and Katsuki are needed to be the ideal hero, and, if the two can "recognise each other and honestly raise each other up," they can "become the best heroes, who both win and rescue."
All Might himself seems to greatly approve of Izuku and Katsuki's friendship, despite the way Katsuki outwardly expresses himself. In chapter 209, after Izuku tells Katsuki he'll catch up to him, All Might says, "that's a good friend you've got," in regards to Katsuki.
In My Hero Academia: Two Heroes movie, although non-canonical, provides one scene where Katsuki is shown to truly care about Izuku's wellbeing. At the end of the final fight, there is a scene where it becomes unclear as to whether Izuku will make it out alive - showing the class onlooking in fear, including Katsuki. Once Izuku is shown to be victorious, we are shown Katsuki smiling as he makes his appearance. Shouto notices this and makes a knowing face towards him, to which Katsuki scoffs in response and looks away, walking off from the rest.
During chapter 217, the two are discussing One for All together with All Might, with them comfortable enough to sit in the same couch. Katsuki and Izuku are also training together, to help Izuku master his new Black Whip quirk. Izuku obtained this quirk in chapter 210, when he got furious as Monoma insulted Bakugou by saying that even though he was the cause of All Might’s end, he is still able to smile. The latter did this to hype up Izuku because he knew they were friends.
In the Eastern side of the fan base, BakuDeku is the most popular ship amongst fans due to their complex and interesting relationship.
In the Western community, the pairing is still widely appreciated, however many believe the two have an abusive relationship, even though it is to be admitted that Katsuki matured and learned to respect Izuku, albeit reluctantly, as the story continues. Due to Katsuki's personal issues surrounding his inability to express himself without using anger and Izuku's past inability to defend himself, some view their interactions as inherently toxic due to the past that Izuku has endured as a result.
There is somewhat of a divide in the fandom due to this discourse, but those who do ship BakuDeku continue to enjoy their relationship evolving as the series develops, whether people are against it or not.
BakuDeku fans found this parallel to their pairing, providing a panel in Kacchan vs. Deku 2 as evidence where Izuku says to himself, "It's not like I could just go and refuse [Katsuki]. Thinking back, our relationship was always weird."
On AO3, BakuDeku is the most written ship within the My Hero Academia fandom tag.
- The term 'Wonder Duo' comes from a mistranslation where All Might calls Izuku and Katsuki the same name before they team up to fight him in chapter 61. It has since become a popular ship name due to its simplicity.
- On April 20th 2018, A fan of the pair bought a whole acre of the moon and named it after Bakugou on his birthday as a present for Horikoshi. Not long after, a star was named after Bakugou too, along with a star named after Izuku. At chapter 106 of the manga, the two were also described as the "Twin Stars of Class 1-A".
- On July 20th 2018, a Twitter announcement on the My Hero Academia: Two Heroes account told all My Hero Academia fans to vote for their favorite pair in the show and the duo that wins will get their character colors shun on the Kyoto tower for promotion to the release of the movie. The poll ended on August 1st, crowning BakuDeku first place with over a whopping one million votes. Izuku's vibrant green and Bakugou's fiery orange lit up Japan's evening sky as their colors proudly glow on Kyoto Tower.
- Izuku's favorite food is katsudon.
- There were poker merch for the series, and Katsuki and Izuku were on the King of Hearts.
- They have an instrumental song together, named "Katsuki and Izuku."
- Season 2's second ending, Datte Atashi no Hero (or Because You're My Hero in English), was written by LiSA, who confirmed that the song's lyrics are written to represent Izuku‘s genuine feelings towards Katsuki.
- Some of the song's lines translate to "you give me courage," "when I see those eyes, I can start running too!" and "I want to try and look at the goal that's only yours and mine."
- The "when I see those eyes" line plays as the ending shows Izuku and Katsuki looking at each other before teaming up to fight, originally against working together; metaphorical for their relationship growing in the series.
- Some of the song's lines translate to "you give me courage," "when I see those eyes, I can start running too!" and "I want to try and look at the goal that's only yours and mine."
- BakuDeku has been featured on Fandometric most reblogged ships list several times:
- It was the seventeenth most reblogged ship the week ending April 15th 2019.
Screenshots and Gifs
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