Todoroki Shoto is the son of Endeavor, the number 2 hero, while Bakugou Katsuki is the former childhood friend of Midoriya Izuku. They both end up in the same class at UA as first year students and are studying to be pro heroes. They start out as rivals, Katsuki seeing Shoto as one of the people he needs to beat on his path to becoming No. 1 and Shoto who is shown to be never intimidated by Katsuki, unlike pretty much any of their other classmates.
In the first team battles, Shoto comments on Katsuki's skill, saying: "He doesn't look like the type to think, but he's more subtle than I expected." He also proceeds to explain what Katsuki did. This is also the first time we've heard Shoto say something. During Shoto's battle, Katsuki is surprised and angry seeing Shoto's effortless win after losing his own battle to Izuku. When he was yelling with tears in his eyes to Izuku, he yells "As I watched the ice guy, I thought: "I can't beat him!". This started off Katsuki and Shoto's mostly one sided rivalry from Katsuki's side and Katsuki starts seeing Shoto as a proper rival.
Shoto and Katsuki only have brief interactions during the U.S.J Incident, together with Izuku and Eijiro they go to help All Might. After the fight with the nomu, Shoto makes a comment to Katsuki about how the whole school wasn't attacked if all the Pro Hero teachers were here.
Just before the Sports Festival begins, when Shoto makes his declaration of war against Izuku, Katsuki (and the rest of the class) is watching them. When the first part of the Sports Festival starts and Shoto starts out with freezing the ground but Katsuki and some others dodge and he declares he won't get him get away that easily. Later when Shoto starts getting really out on front, Katsuki says that he won't let Shoto get ahead of him. When Katsuki finally catches up to Shoto, he says he shouldn't have declared war to the wrong person (Aka he should've been seeing Katsuki as his greatest rival). They continue running while attacking each other and stay in the lead until Izuku cuts in and gets ahead of them. They then stop fighting to catch up to Izuku but lose. During the Calvary battle they don't interact much outside of Katsuki going after him and putting Mina on his team to deal with Shoto's ice. However he does mention Shoto by name, while he usually calls all of his classmates by nickname, most likely because he doesn't care about them enough to remember their names. However Katsuki sees Shoto as a real rival, therefore he remembers his name, the only other classmate he called by his name is Kirishima, who he called by name for the first time in the cavalry battle since he might an impression on him somewhat when joining Katsuki's team (considering he and Izuku are childhood friends it's safe to assume he knows Izuku's name, he just didn't call him by his name).
While Shoto is talking about his past to Izuku, it is shown that Katsuki is eavesdropping on them and is surprised at Shoto's past. During Izuku and Shoto's battle, Katsuki is paying a lot of attention and makes his own analysis of Shoto's quirk. After Katsuki and Shoto win the semifinals, Katsuki and Shoto look/glare at each other immediately. Before their battle, Katsuki accidentally walks in Shoto's waiting room and is furious at how Shoto barely bats an eyelash to him and blows up the table, asking him where he's looking at and how's it's no way to treat his opponent in the final. When Shoto immediately starts asking about Izuku it makes Katsuki even more furious. Katsuki asks him who the hell cares about Izuku and Shoto's family drama and his feelings. Katsuki says he doesn't care about any of that and that Shoto should just use his fire against him as well and walks away. Katsuki is excited about the chance to beat Shoto indisputably while Shoto uses his full power.
Their battle starts and Katsuki has the upper hand. When Shoto's father Endeavor yells at him to use his left side, Shoto looks at his father, making Katsuki angry at him being distracted. Shoto doesn't use his fire because of his father. Katsuki tells him to stop screwing around and asks if he isn't strong enough for his fire. Katsuki feels like he's being made a fool out of and tells Shoto he can't get an indisputable first place if Shoto underestimates him. He then says to him: "There's no point if I can't get higher than Deku (Izuku). If you have no intention of winning then don't stand before me! Why the hell are you just standing there, dammit!" After Izuku encourages Shoto, Shoto starts emitting flames and Katsuki gets excited. Katsuki thinks that Shoto should only focus on him when he's standing in front of him. Katsuki starts his final attack and Shoto mentally apologizes to Katsuki, meaning Shoto does recognize Katsuki's feelings as valid and feels bad. Just before Katsuki does his final attack, Howitzer Impact, Shoto thinks about his past again and stops emitting flames and just takes Katsuki's attack. After the smoke settles, it becomes clear that Shoto got blown out of bounds and is unconscious. Katsuki is declared the winner, but Katsuki is furious when he realizes Shoto didn't use his flames. He runs up to Shoto, grabbing him by the collar and yelling at him with an angry but despaired voice: "Hey, stop screwing around! Didn't I tell you there was no point, dammit? To get first place like this! Like this? Like..." Katsuki then passes out next to Shoto due to Midnight's quirk.
During the award ceremony Katsuki had to be restrained on stage and refused to accept the victory because he didn't win from Shoto's full power. Katsuki most likely felt like Shoto didn't see him as a proper rival, while Katsuki did see Shoto as a strong rival and the most skilled in class next to him. While Katsuki was frustrated at first seeing Shoto's skill, Shoto wasn't focused on him even during the fight and was focused on Izuku (who he already felt somewhat both inferior and superior to) and his father. In Katsuki's eyes, Shoto saw Izuku as more of a rival than Katsuki, most likely feeding more into Katsuki's sense of inferiority to Izuku.
In the first episode of season 3, when during the swimming competition, Katsuki, Shoto and Izuku are to 'swim' the finals, Katsuki suddenly starts saying Shoto should better not hold back against him like at the Sports Festival and he should come at him seriously. Shoto tells him he will. Afterwards when Katsuki and Eijiro walk home together, Katsuki is angry at Aizawa for stopping the race just before the finals and Eijiro says he gets it but he should calm down and says "Midoriya and Todoroki are classmates- and friends right?" Katsuki tells him to shut up, but doesn't deny it and instead says it doesn't matter who it is, he needs to beat them regardless.
When the entire class is going through the Beast Forest, Katsuki and Shoto take out an earth beast together, afterwards they run side by side and Katsuki tells him not to get in his way, while Shoto tells him he's not in his way. After Katsuki calls Kota a 'precocious brat', Shoto makes a comment about how he's kind of like Katsuki. Katsuki says: "What? Not at all! Anyway, shut up, you GG bastard!" Shoto apologizes with a deadpan face. When the test of courage starts, Katsuki and Shoto are paired together, much to Katsuki's reluctance who immediately demands a new partner. They do part of the test of courage together before the attack, a scene shown where Katsuki and Shoto simultaneously let out an 'Oh' because of Yui who pops out of the ground.
When the LOV attack during the test of courage, Katsuki and Shoto are still together with Shoto carrying a person from 1-B on his back. Shoto says what they should do, although Katsuki starts saying he shouldn't tell him what to do (although but less bite) they get interrupted by Moonfish with Shoji's cut off hand. Katsuki asks Shoto who was in front of them, Shoto says it was Shouji and Tokoyami. When they get notified Katsuki is the target of the LOV, Katsuki ignores the warning not to act alone and rushes towards Moonfish. Shoto manages to save Katsuki by stopping Moonfish's blades from impaling him with his ice. Shoto tells him not to rush into things. Katsuki ignores this and rushes in again but Shoto saves him with his ice again. When Katsuki starts letting off small explosions, Shoto tells him if the trees catch fire and it spreads they'll be surrounded and die. Katsuki yells at him that he knows that. Moonfish continues the assault and Shoto's ice is the only thing stopping him. Katsuki tells Shoto to just cover the fire with his ice but Shoto says it's dangerous since the explosion will impair his vision as well. The fight gets interrupted by Shoji, Izuku, Tokoyami and an out of control Dark Shadow. Katsuki stops Shoto from stopping Dark Shadow before Moonfish is dealt with. After Moonfish got taken out, Shoto and Katsuki stop Dark Shadow together. When starting to escort Katsuki to safety, Shoto tells Katsuki to walk in the middle, although Katsuki yells at him not to protect him. Shoto then tells Katsuki to make sure he keeps up and Katsuki tells him not to tell him what to do.
When Katsuki and Tokoyami get taken my Mr. Compress, Shoto tries to stop him with his ice. Shoto, Izuku, and Shoji go after Mr. Compress and fight the villains. When the orbs containing Katsuki and Tokoyami fall out of Mr. Compress' mouth, Shoto lunges for Katsuki's one, but it got taken away just before he reached it by Dabi. Shoto, Izuku, Tokoyami and Shoji watch as Katsuki gets takes away by the villains.
When the class visits Izuku in the hospital, Shoto is the one bringing up the fact that Katsuki isn't with them. Eijiro brings up the plan to save Katsuki, saying that Shoto and him were at the hospital yesterday because they couldn't stay at home and they decided to go save Katsuki together. They invite Izuku and tell the class their plan. Together with Momo and Iida, the 5 of them go to what is possibly Katsuki's location. In the train, Shoto reminds them that what they're doing is selfish and they can still turn back. When they arrive at the location and All Might and Katsuki are in a pinch, Izuku comes up with a plan to get Katsuki away and Shoto creates a giant ice ramp so the others can get Katsuki out. When Katsuki's out, Shoto escapes with Momo. After watching All Might's fight, they bring Katsuki to the police station.
When Katsuki gave Eijiro money for the night scopes he bought, instead of being distracted by Denki, Shoto was the only one of the class looking at Katsuki (minus Eijiro). During the provisional license exam arc, Katsuki and Shoto don't really interact, however, they are the only ones in class 1-A to fail the license exam and are going to take extra classes to get their provisional licenses. However in episode 20 of the third season they do interact. They're together in a class with Ochako, Izuku, Iida and Asui. They have to catch a hypothetical villain. When Katsuki says that one of the hostages killed the villain, Shoto asks him for the motive, to which Katsuki yells in his face that it's obviously the jewelry. Tsuyu points out that it's too reckless and Shoto says the villain was holding the jewelry, angering Katsuki. Shoto is also one of the people that stopped Katsuki when he was going to get violent. After Izuku and Katsuki's fight they have house arrest, so Shoto asks what Katsuki is going to do about it. Katsuki tells him to shut up and that it's none of his business.
In the fourth season, Shoto and Katsuki are shown to go to the extra classes together for the provisional license. In episode 2 of season 4, Shoto says Katsuki's lucky that after his fight with Izuku he can still take the extra classes and that they need to catch up as soon as possible, Katsuki says he needs to shut up and walk behind him. Later when talking in the common room about the work studies and that Izuku got accepted, Shoto and Katsuki are standing together away from the others and Shoto makes another comment about how they need to catch up as soon as possible. Katsuki makes an annoyed sound in response. When hearing Tokoyami is going to do a work study with Hawks, Shoto says they need to catch up as soon as possible again. Katsuki yells at him to stop saying that. When Shoto is going to say it once more, Katsuki yells in his face to shut up. Shoto remains unfazed. Later Shoto and Katsuki come to class with injuries from their extra classes. When Denki and Mina talk about the classes, Katsuki yells at them to not talk like they're not there.
On the night the work study students returned, Shoto and Katsuki both go to bed early for their extra classes. The next day they go to the extra classes, Katsuki tells Shoto to walk behind him and then Shoto says he feels bad about making Aizawa take them after yesterday, to that Katsuki says he isn't going to make small talk with Shoto. Together they go to the extra classes. They run into the Shiketsu students in the building. After they got dressed, Katsuki sees Inasa and Shoto talking, with Inasa trying to befriend Shoto and he says that makes him feel sick. When Endeavor yells encouragement to Shoto, interrupting their class, Katsuki looks towards Shoto, who's turned away from Endeavor. During class, Gang Orca pulls apart Shoto, Katsuki and Inasa (+Camie) for a special trial. Later when Katsuki says a little violence is necessary for kids, Shoto says that isn't true, to which Katsuki responds that's how he was raised. Shoto responds that there should be a better way, Katsuki remembers Shoto's past (only shown in manga) and says he should show him his way of doing things then. When the kids attack and Camie makes an illusion of Shoto who says with a smile: "Hey, there. I want to see your cute face. Don't spoil it with wrinkles." Katsuki bursts out in a fit of genuine laughter for the first time at this and says: "I thought it was good! Glamouroki!" Shoto asks if it was really that funny. After Shoto and Inasa make a giant ice slide, Katsuki looks at Shoto who's surrounded by the excited children. Also when Katsuki calls out to Inasa and Shoto, he calls Shoto 'Todoroki', while he usually calls him by a nickname. Later when they're outside preparing to go home and Endeavor starts talking to Shoto, Katsuki looks at them and in the manga Katsuki looks back at Shoto after his talk with his father.
During the second half of season 4, Katsuki and Shoto's interactions are minimal. However when Katsuki starts protesting about the class providing stress relief for the other students, Shoto tells Katsuki not to protest when he didn't even participate in the discussion. After Katsuki explains his reasoning and says: "Let's kill UA with our sound!" Shoto and Iida realize that Katsuki has been carrying a heavy burden since he got kidnapped.
During the Joint Training arc, Shoto and Katsuki don't interact much, outside of a bit of commentary. After the matches with class 1-B, Katsuki overhears Izuku and Shoto talk about Black Whip and Shoto figured out it was a second quirk, however Izuku denies this and Shoto believes him. Katsuki then thinks: "You're sharp and dull at the same time, huh, Half-and-half bastard?".
A different day it was shown that Shoto and Katsuki are doing the exam so they can get their provisional licenses. On the way back after getting their licenses, they encounter a group of villains stealing bags from civilians. They immediately decide to stop the villains themselves. All Might comments on the fact they've only got their licenses for 30 minutes, so Katsuki asks: "Then how many minutes do we have to wait until we're heroes?". Together they stop the villains in their tracks, working well together and not once getting in each other's way. They know each other's strengths and their own and manage to stop the villains without anyone getting injuries and not damaging buildings even though they have destructive quirks. They never tried to be better than the other. After defeating the villains, Katsuki notices the move that Shoto used to take out the leader was the same one as he used at the Sports Festival. Shoto confirms this and asks if he is injured. Katsuki denies this angrily and Shoto asks about the woman who didn't evacuate and Katsuki denies this as well. Both of them get pat on the head by All Might. Afterwards Shoto still has to melt the ice and Katsuki says he won't help. When they get home they get congratulated by the entire class.
Katsuki and Shoto get interviewed later and the interviewer comments on how they work together. Katsuki denies they work well together, while Shoto says they're friends. Katsuki says he shouldn't spout random bullshit and asks since when the hell the were friends. Shoto says they spent a lot of time together because of the extra classes. Katsuki says that the amount of time they spent together has nothing to do with being friends. However this means that Shoto considers Katsuki a friend even if Katsuki doesn't and has no ill will against him. When the interview gets out, Katsuki has both his face and his answers edited out. Later Shoto apologizes for being the reason why Katsuki is edited out, but Katsuki tells him to not be so cocky and that he holds no influence over him. Shoto responds with a deadpan 'I see'. After the interview practice, Shoto and Izuku are talking and Katsuki looks at them.
While cleaning up after the Christmas party, Shoto invites Izuku and Katsuki to go with him for the work studies to his father. They both accept. When they meet up with Endeavor for the work study, Endeavor says he had wished Shoto came alone, Shoto says he shouldn't complain when he already accepted. Katsuki says to Endeavor: "I've been thinking this since the extra classes, but you're a real stick-in-the-mud, aren't you?(manga)/but you're kind of cringy(anime)." Endeavor asks if Shoto's really friends with this brat (Katsuki). Katsuki says that it's fine as long as he's able to see the No. 1 work. Endeavor yells at Shoto that he told him to bring his friends. When they arrive at the agency and Burnin' says that Izuku and Katsuki will most likely end up working with the sidekicks since Endeavor only wants to train Shoto. Katsuki is angry and says he only came here so he could watch how the No. 1 works. Izuku tells him to calm down, but Shoto says that's indeed not what he expected and he'll talk to him about it. Endeavor interrupts and says he'll train all 3 of them. Izuku and Katsuki watch as Shoto tells Endeavor why he came and that he should stop trying to act like a father in front of his friends. This also means regardless of what Katsuki says, he considers him a friend.
During the work study and seeing Endeavor work in person, Shoto asks Katsuki if he noticed. Katsuki says that there's nothing that Shoto could realize that Katsuki can't with an irritated smile and tells him to spit it out. Shoto talks about Endeavor's Jet Burn and using his flames to propel himself. Katsuki says it's a rip-off from his Explosion and asks him if he just realized it. Shoto smiles and says: "Yeah, I took the long road. (anime)/Yeah I suppose you could call it a rip-off. (manga)" Shoto and Katsuki get the same assignment from Endeavor and Katsuki asks why he's always paired up with Shoto. When eating something on the roof of a building, Shoto and Katsuki are seen eating the same thing. The 3 of them sleep at the agency and at one morning, Shoto says that they were close to surpassing Endeavor's speed yesterday and that today they would surpass him. In the anime Katsuki says that he was the only once close and that Shoto was too slow, which meant he was better than him. Shoto (and Izuku) ignores this and Katsuki yells at them not to ignore him. In the manga, Katsuki says that the both of them are slower than him, making him better to which Shoto responds: "Yeah, I'm still not used to focusing my flames."
Later, Izuku and Katsuki are invited to dinner at the Todoroki house. Katsuki demands why to which Shoto responds his sister invited everyone for dinner, Katsuki demands why again and Shoto says it's because she wanted to meet his friends. Katsuki yells at him to tell her that they've never been friends. During the dinner tensions between Shouto's brother Natsuo and Endeavor rise causing Natsuo to leave early. When cleaning up, Izuku asks if Katsuki also knew about the Todoroki family drama, Katsuki says that they were the ones talking about it right in front of them. Katsuki also yells that Shouto and his sister shouldn't talk about their drama when they have guests over and Katsuki listens while Shouto's sister explains why Natsuo still is so aggressive towards Endeavor. When they leave, Katsuki says to Shouto's sister to teach him her mapo tofu recipe, Shoto says she can just text it to him and he'll text it to Katsuki. Later when Ending attacks, Shoto, Katsuki and Izuku work together to save Natsuo and civilians and take out Ending with flawless teamwork, surpassing Endeavor.
In the final episode, Katsuki asks who cut the chives, Shoto says he did it and Katsuki says his sister would cry if she saw it. When Katsuki does the cutting himself, Shoto comments that he's good at it, which Katsuki responds to by saying he's just bad at it.
After Katsuki got pierced by Tomura's tendrils, Shoto fishes Katsuki out of the air, as well as Endeavor and Izuku, saving them from falling. When he gets down he immediately checks if they're still breathing and to his immense relief they are.
In the aftermath of the Paranormal Liberation War, Katsuki asks after waking up first about Izuku and Shoto. After Izuku left Katsuki and Shoto lead the class to confront Endeavor about Izuku's whereabouts. When Shoto starts getting angrier at Endeavor, Katsuki cuts in and places his hand on Shoto's shoulder, either to calm him down or a way of saying he got it from here. However either way is something that is extremely rare coming from Katsuki, because he doesn't tend to initiate positive physical contact. He's been seen accepting it, however initiating it, is not something he really does especially with his classmates. When the class finally finds Izuku, Katsuki, Shoto and Momo use a combo to take out the villain Dictator. Later they are seen standing back to back, and Shoto uses Flashfreeze Heatwave to propel Katsuki and Iida.
After hearing that Shiketsu has something similar to the UA barrier, Katsuki and Shoto look at each other and simultaneously say: "They did say that..."
In chapter 327, after Eijiro asks Shoto if he's not frustrated, Katsuki is looking at Shoto behind Kirishima as the only other one in the panel, which is another instance of Katsuki looking at him when he's talking about his past. These instances show that Katsuki is interested about what Shoto's mental state is and can also be seen as Katsuki caring/looking out for Shoto.
Later, after class 1-A moves to the stronghold Troy, Shoto, Iida, Eijiro and Katsuki are in Shoto's temporary room. With Eijiro sitting upright on his bed and Katsuki comfortably laying on Shoto's bed. Shoto apologizes for worrying them but assures he's fine now. After Iida makes a comment on them being similar, Shoto comments that he can't compare himself to Iida since Shoto doesn't even know what Touya likes. Katsuki then speaks up and says that he'd bet he likes udon. Shoto laughs at this and says if that's the case, he wouldn't mind sharing some udon with him. This is yet another instance of Katsuki seemingly expressing concern for Shoto and Shoto's mood seems to be lifted somewhat after Katsuki's comment.
During Shoto's fight against Touya, he has flashbacks from before the fight but after Izuku came back. While Shoto explains his new move to Izuku who missed everything and both him and Denki are fascinated by the cold fire and Shoto explains something he said before, Katsuki suddenly pipes up that he shouldn't forget he's the strongest and calls him a loser. While Shoto thinks back on how the class was always there beside him, Katsuki is one of the people in the foreground. And when he gets flashbacks of the class while he thinks of how they were there for him, Katsuki is also shown twice.
After hearing Shoto defeated Touya, Katsuki grins and says: "Of course he won... that Todoroki..." This shows he has complete faith in Shoto's skill and mental strength, as defeating his own brother took a lot of both, even when others worried. Also not everyone was shown of class 1-A, like Izuku, Momo, Denki and Tokoyami, but Katsuki was and was also the only one at the UA location. It also marks one of the few times Katsuki called Shoto by his name.
Shoto and Katsuki's relationship has grown a lot since the beginning, going from rivalry and dislike to friends who trust each other and work well together. They have shown multiple times that they work well together and trust each other to follow each other's plans without complaint. They trust in each other's strength and although Katsuki had denied it, it is clear that they've become friends.
My Hero Academia Movie 1: Two Heroes
In the movie which takes place between the Final Exams and the Forest Training Camp arcs, Shoto and Katsuki first interact when Katsuki is yelling at Izuku for having a time close to his after doing an attraction on island where you have to destroy the villains as fast as possible but they get interrupted by Shoto who gets a time even faster than Katsuki's. Katsuki goes to him and yells at his face: "Appearing suddenly trying to make everyone think you're amazing, you bastard?!" Shoto asks if the others are also on the island, Katsuki yells at him not to ignore him and asks why he's here anyway. Shoto says he's here to represent his father. The lady who works at the attraction tells him people are waiting for their try, Katsuki yells at her. Later when villains attack Eijiro (and Katsuki), Shoto interrupts and saves them. Shoto gets the others away while he, Katsuki and Eijiro fight the 2 villains. However Eijiro gets taken out at the beginning of the fight and Shoto and Katsuki are left to take on the villains. When asked who they are, they both respond they won't tell them. They both take on one villain and don't get in the way of each other. Katsuki eventually takes out one, so the other villain attacks Katsuki but gets Katsuki's explosive sweat on his palms, which Shoto explodes with his fire. In the fight they work somewhat together and don't get in each other's way at all. After the fight Eijiro seems to be unharmed and the 3 of them take on the robots.
When Ochako nearly gets attacked by the robots, Shoto, Katsuki and Eijiro interrupt. Shoto says they'll stop the robots right here, Katsuki says to not tell him what to do. Eijiro says that they make a good combination though, which Katsuki denies. When Melissa and Izuku nearly get blown away, Shoto says to Katsuki to make the propeller face Melissa and Izuku, Katsuki says that he said not to tell him what to do, but he does it regardless, which ends up saving them. Later when All Might is in a pinch, the other classmates arrive and Shoto and Katsuki end up saving All Might. When All Might and Izuku attack the villain together, Shoto and Katsuki end up yelling together: "Get him!" When the villains gets defeated, Shoto catches Katsuki smiling and is smiling himself. When Katsuki catches him staring he looks away with a scowl.
My Hero Academia Movie 3: World Heroes' Mission
World Heroes' Mission has a prequel manga called: My Hero Academia Special Spin-off: Endeavor’s Mission. In this prequel, Shoto and Katsuki don't interact much by themselves although they work together to face Endeavor with Izuku. In one panel they are seen to be admiring the special suits together and when they're designing their stealth suits, Shoto thinks about how detailed Katsuki's gauntlet designs are.
In the special booklet given to the ones who watched the movie first in theaters, there is a 9 pages long manga short where Endeavor, Shoto, Katsuki and Izuku are at the airport preparing to board the airplane. This has also been adapted into a 5-minute long OVA. In the OVA, it is shown that Katsuki starts listening in the conversation Shoto and Izuku have after Shoto starts explaining that the way Izuku is trying to calm himself down is said to not work when he doesn't swallow it. When Katsuki appears to be nervous, Izuku is surprised while Shoto assures him he'll be fine if he can speak English, Katsuki tells them to shut up. After Shoto says that he wants to sit next next to Izuku and Katsuki instead of his father, Katsuki asks if he still thinks that the 2 of them are friends. Endeavor responds to Shoto but he demands to sit next to his friends and Katsuki yells that they're not friends and if Shoto wants to enjoy the plane ride strapped to the tail of the plane. In the OVA, Shoto tries to grab Endeavor's ticket and then Katsuki gets close to Shoto's face and tells him not to ignore him, Shoto proceeds to ask Katsuki to switch with him and Katsuki yells at him to stop acting so nice. Katsuki grabs Shoto's tie and continues pulling it, but Shoto ignores Katsuki's complaints about not being friends, treats and tie-pulling in favor of arguing with Endeavor. In the OVA, when Katsuki grabs Shoto's tie, Endeavor yells and asks what Katsuki is doing to Shoto. Their arguing gets interrupted by Hawks.
We first see the 2 interact at the beginning of the movie, when the heroes are moving towards the headquarters of Humarize, Shoto reminds Katsuki and Izuku what their jobs are and to not let their guards down. Katsuki asks him who he thinks he's talking to. Shoto and Katsuki take the lead together and Shoto reminds him to not be too rough since most of the members are quirkless, but Katsuki tells him he already knows. The 2 then work together, Katsuki stops the enemies in their tracks and Shoto then freezes them. They continue to move forward together. After the mission fails, Shoto, Katsuki and Izuku are carrying groceries for the team and Katsuki angrily asks why they have to run errands. Shoto explains that it's because they're the lowest ranking members, making Katsuki turn to him angrily, Shoto further explains that they are only on the mission because they're interning with Endeavor. When Katsuki and Shoto are back at the hotel with Endeavor after stopping robbers, while Midoriya is busy with Rody, they are berated by Endeavor for going after a petty crime when they're in the middle of an extremely important mission. Shoto and Katsuki arguing with him, Shoto says heroes are supposed to save those in trouble and Katsuki says that Endeavor didn't learn them to assign importance to their jobs. After Shoto finds out where Izuku is headed, who's now being accused of mass murder and on the run with Rody, Katsuki came in the room, but immediately gets dragged out by Shoto, who grabs him by his arm. Katsuki asks him where they're going but doesn't try to struggle out of the grip. They leave the building and Katsuki guesses that it's about Izuku, Shoto says he'll explain more later, but for now they need to shake the police guards who are secretly following them. Katsuki tells him not to order him around and they leave.
In the train to Izuku's location, Katsuki asks Shoto if the cases got switched. Shoto confirms and says they're must've been some kind of mix up and Izuku is carrying the case which has something to do with Humarize. Katsuki says that it must be the reason the police is chasing him. Shoto says it's likely and that he guesses that whatever Izuku is carrying, is very important, since the police would not operate on such a large scale if it wasn't. Katsuki says that Humarize has infiltrated the police force, Shoto agrees and says that they have to be careful. Katsuki says tells him not to order him around. While Izuku and Rody are attacked by 2 villains with a helicopter and are in a pinch, Shoto and Katsuki arrive. Shoto saves Rody and freezes one of the villains, but gets attacked by the 2nd villain. It's then that Katsuki arrives and cuts in, attacking the villain and asks: "Where are you looking?!" and in the dub he says "Oh, don't even try it.". While Shoto and the frozen villain are talking, they get attacked by the 2nd villain again and Shoto tells Katsuki to get her. Katsuki tells him not to give him orders, but starts doing what Shoto told him to. After learning about Flect Turn's plan to take down the top heroes and knowing they won't retreat no matter what, Shoto says they'll use the key themselves to disarm the bombs. Izuku questions how they're going to do that, Katsuki immediately tells Shoto to move and in the dub he says he's on it and he pushes Shoto away from the computer.
In the dub, after Katsuki tells Rody that extras like him should stay out of the way, Shoto tells Rody he has a point. While Shoto and Izuku move further in the Humarize base, Shoto says they'll leave the rest of the Humarize members at the entrance to Katsuki. Katsuki yells at him to not give him orders. After the fight, Shoto and Katsuki are seen unconscious in a helicopter together, the 2 being transferred to a hospital.
Jump Festa 2016 Special, Rescue! Rescue Training!
After the USJ incident, before the Sports Festival, the class is back at USJ for rescue training. Shoto, Katsuki, Tokoyami and Yaoyorozu are paired together to save Izuku, Iida and Ochako who are at the bottom of a cliff. Shoto asks who is going down, Katsuki is angry and says that this bastard (Shoto) doesn't listen and says he'll need to teach him. Katsuki says to blow up the mountain, Shoto sighs and ignores him. Shoto instructs the others what to do. This angers Katsuki and he yells at him to stop deciding on his own and grabs his collar. Shoto says that this the best way and slaps away Katsuki's hand. He says he won't waste his time this training and walks away. This makes Katsuki furious and goes to attack him and Shoto reacts but Yaoyorozu interrupts and scolds them and says to first reassure the victims. They do end going with Shoto's way and Yaoyorozu instructs Tokoyami and Katsuki and Shoto pull together. When Todoroki gives him instructions again, Katsuki tells him to shut up and just do it, although much more subdued than before.
Make It! Do-or-Die Survival Training
During the survival training Katsuki puts the electricity on again with Denki and Eijiro and Shoto says the ones who would think about that would be Momo, Izuku and Katsuki. After Denki, Eijiro and Katsuki save the dummy and Katsuki explodes a big stone, Shoto and Tokoyami are surprised and figure out it's Katsuki. Shoto then realizes that Katsuki is continuing the exercise despite the circumstances. When Katsuki, Eijiro and Denki are in a pinch due to the rapidly rising water, Shoto and Tokoyami save them. Shoto tells them to climb up and Katsuki yells: "Who the hell asked for your help?!" When the trio climbed up, Tokoyami, Eijiro and Denki go to the elevators while Shoto stays back to buy time and Katsuki stays behind to save Shoto. When Shoto asks why Katsuki stayed behind, he says he didn't want to owe him a debt, Shoto says he doesn't care about that and they should get out of there. Katsuki explains that it's no use running and that the pressure due to Shoto's ice will make water pressure jets with debris. Shoto says: "You've already thought of a way out, right?" This shows Shoto has faith in Katsuki's intelligence. Katsuki explains his plan to Shoto and smiles. Shoto asks if he can do it, which Katsuki confirms. Izuku then comes to help them, angering Katsuki. When they get to a higher floor, Katsuki ends up with an injured leg, Shoto says he should hold on to him and Izuku and holds out his hand, but Katsuki rejects it, saying the injury is nothing. Shoto says not to push himself, Katsuki says he doesn't need his help. When Katsuki gets up and walks, Shoto points out that he's unsteady on his feet, to which Katsuki responds that his feet just won't do what he tells them to. Izuku points out that Katsuki stayed behind to save Shoto, which Katsuki says is only because he didn't want to owe him anything. Izuku says that Katsuki saved him and Shoto says that he was saved too by Katsuki.
Official Drama CD: An Assassin from the Union
At the end of season 2, when Izuku encounters Tomura, Katsuki and Shoto didn't go with the rest of the class to the mall and they happen to meet each other. Shoto calls out to Katsuki and Katsuki asks why he's randomly talking to him. Shoto asks why he's not with their classmates. Katsuki says they're just stepping stones for him, nothing more, nothing less. Shoto says he seems close to Eijiro though. Katsuki asks if he's blind. Shoto says: "I see. Sorry for talking to you. I'm going home now. See you." Katsuki responds that that sounds great and that he hopes he'll die on the way back. Suddenly a random person walks up to them and starts talking about the Sports Festival, Katsuki yells at him not to talk about that. Shoto scolds him, saying he shouldn't do that, especially with someone he just met. Katsuki yells at him, asking who the hell cares about that. When the stranger reveals himself to be a villain, Shoto reminds Katsuki they're not allowed to use their quirks or they might be expelled, but Katsuki gets angry and reminds him there's a villain right in front of them. Shoto still says that it's against the rules and they should get out of here and contact the pro heroes. When Shoto grabs Katsuki's arm to get him away, he finds out that his hand is stuck. Katsuki hasn't realized yet and tried to push him off, but his hand is stuck to Shoto's chest. The villain explains his quirk and Katsuki starts moving to get to the villains but they get stuck more together. The villain says: "How beautiful! It seems like you two are in a lovely dance together!" The villain takes a picture of them, Katsuki tries to move again but Shoto says to stop. The villain moves Shoto's arm on Katsuki's back and says that now it really looks like they're passionately dancing with each other. The villain pushes Shoto on Katsuki and they get stuck more together. Katsuki tells Shoto to get off, Shoto says he would if he could. The villain continues taking pictures, saying it looks like a lover's embrace. Shoto and Katsuki tell him to stop taking pictures. The villain ignores this and continues. Shoto says to Katsuki that they should move to the alley when the timing is right and Katsuki agrees. The villain realized and sticks their feet together so they fall. The villain takes Shoto's head and makes him go closer to Katsuki. The villain explains his plan to post the pictures online and have them haunting them throughout their career. After the villain is done explaining, Shoto tells him to do as he pleases. To take as many pictures as he wants and that he wanted them to smile for the camera as well if he remembers correctly. Katsuki is confused but Shoto tells him to play along. The villain asks Shoto if he's surrendering, Shoto denies this and says he won't give up on becoming a hero, just that he can take as many pictures as he wants. Shoto asks the villain if he has any requests. The villain tells him he should be struggling more or else he won't be satisfied. Shoto figures out that the villain is very honest. The villain says to satisfy him, to feel ashamed, to struggle more. Shoto tells Katsuki to endure it and says they'll headbutt the villain. The villain's quirk stops and Katsuki and Shoto are freed. The villain cries out in despair, saying: "No, why is it like this?! My beautiful models!". This angers Katsuki and he asks: "Just who the fuck are you referring to as models, you damn pervert?" Shoto says Katsuki shouldn't use his quirk. Katsuki asks him why he's still onto that and Shoto says to Katsuki to bring him down without his quirk and without killing him. Katsuki says that it's too complicated but complies.
Official Drama CD: Season 3 Volume 8
The first part of the drama is Izuku and the brother of the villain talking and the villain mentions seeing Shoto and Katsuki at the Sports Festival and compliments them. He also gets the location of the 2 from Izuku indirectly. When Shoto and Katsuki are walking to the dorms together and Katsuki calls Shoto an eyesore and tells him to not follow him. Shoto tells him to not say unreasonable things and that obviously he has to walk the same direction as him. Katsuki tells him he doesn't care and to walk around the world first. Shoto asks if Katsuki is a child. The villain approaches them then and asks if they're Shoto and Katsuki. They confirm and the villain compliments them about the Sports Festival. Shoto thanks him while Katsuki yells at him to not mention that. Shoto scolds him for yelling at someone he just met. The villain starts talking about them failing the Provincial Hero license exam. Shoto asks why he's talking about that and Katsuki asks him if he wants to fight. The villain says that he's just stating facts and continues about people like them failing the exam and that they're failing in their life. Katsuki grabs his collar and asks if he's got a death wish. The villain stutters and asks what he's doing. Shoto tells Katsuki to stop since they're not allowed to fight or use their quirks. Katsuki relents and tells the villain to get lost before he loses his temper. The villain says with Katsuki's attitude he's disqualified as a hero and pro. Katsuki gets angry and says he'll kill him. Shoto calls his name in warning and Katsuki asks how he can keep quiet after being insulted like that. The villain taunts Katsuki and asks if he's going to hurt an innocent civilian. Katsuki asks what he's going to do if he says yes. The villain taunts him further and says he'll report him and his career will be over and uses a Japanese word play. Katsuki asks what the word play means and Shoto explains it to him but Katsuki says that he doesn't need to explain it to him because he already knew. The villain taunts him again and asks if he's not going to punch him. Katsuki tells him to prepare to get hurt and Shoto yells that he'll be expelled. Katsuki sees Shoto's point and curses. The villain taunts yet again and this time Shoto steps in. He says that this is too much and while Katsuki might be rude, he's trying hard everyday to be a hero and he even goes to the remedial course. He then says that he needs to stop insulting Katsuki and that he's also reaching his limit. The villain asks if he's putting up with him and Shoto confirms. The villain says his quirk should be working now. The 2 suddenly find themselves unable to move. Shoto recognizes the villain's face as looking like the man that had stuck Katsuki and Shoto together in the past and asks if Katsuki recognizes him. Katsuki goes to deny but also recognizes him. The villain reveals himself as his brother and Shoto tries to use his quirk but is unable to. The villain cuts both of their shirts open. Katsuki yells at him and Shoto says he'll follow his brother to jail. The villain reveals his plan to be similar to his brother's by posting photos of them doing perverted things and destroying their careers. Katsuki calls him a pervert and the villain prepares to make his next move. Izuku intervenes. Izuku also gets caught in the villain's quirk which he explains as 'Endure' which causes you to be unable to move when you put up with him. Katsuki suddenly says that he can move and Shoto agrees. The villain is surprised and Shoto says that they stopped putting up with the villain. Katsuki says that he's just as stupid as his brother and Shoto says he talked too much about his own quirk. The villain asks why they're approaching him, Katsuki says it's because he can't stand him anymore and Shoto agrees. The villain asks if they're going to hurt an ordinary citizen and Katsuki says that's bullshit and Shoto says he's a villain. Then the villain asks if they're going to beat him and Shoto says that it's a yes. Izuku tells them to calm down but Shoto says they can't do that and Katsuki says you'll be caught in his quirk then. Shoto tells Katsuki to do whatever he wants and to not hold back. Katsuki tells him of course and blasts the villain. Izuku later explains that after Shoto and him explained, they forgave Katsuki for using his quirk.
Despite saying he won't do what Shoto says, Katsuki usually does it anyway because he sees that it's the best option. Even if he doesn't like being ordered around, he still usually follows through with Shoto's plans.
- Part 1 (After internships, before exams): In response to Katsuki's argument about having different strengths to Iida, Shoto speaks up and says that he has a point about people having different strengths. After being asked if he thinks so, Shoto says he just means it's hard to picture Katsuki saving anyone. Katsuki yells at him to try to say that again.
- Part 6: While Katsuki blasts towards the villain, Shoto shoots a blast of ice at the villain, which Katsuki dodges mid-air with lighting fast reflexes. Katsuki yells at him to watch it and calls him half 'n' half bastard again, but the ice manages to freeze the villain's feet, allowing Katsuki to straddle the villain without any problems.
- Part 1 (Studying for final exams): After a child's question that mentions the Sports Festival, Katsuki is reminded of how Shoto had handed Katsuki the win by not giving it his all in the final match and Katsuki snaps.
- Part 2 (After moving into dorms): When his attempt to save Recovery Girl fails and they both become trapped by Hatsume's invention, Shoto thinks of Eijirou and how his reluctance to sit back idly while Katsuki was kidnapped had inspired Shoto to take action as well. Shoto had understand how Eijirou felt because he had witnessed first hand when the villains had snatched the compressed orb holding Katsuki during the attack on their training camp, which was the reason he had joined the rescue effort.
- Bonus (Fantasy setting): After Katsuki says they need to win to get through, Iida says they should retreat as they couldn't defeat a dragon tamer, but Katsuki doesn't let them and Shoto is the only one striking a battle-ready stance while saying: "Looks like we’re in for a fight.”
- Part 3 (New Years' Eve): When Natsuo asks about his friends, Shoto also mentions Katsuki, saying that he thought he might get closer to Katsuki since they had to do that license course together, but it didn’t turn out that way. Natsuo asks himself if they got into a fight, but Shoto doesn't further elaborate.
- Part 4 (Work study): While Katsuki, Shoto and Izuku sit in the cafeteria together, Katsuki leaves a seat open next to him and Shoto, so he sits as far away from Izuku. After Izuku asks Shoto if he already figured out the thing about condensing your power to a point and Shoto answers that he feels like he's getting close, Shoto asks Katsuki if he figured it out already. Katsuki says that he got the gist of course and asks him if he would cram it already. Shoto apologizes and goes back to slurping his soba.
- Part 4: After Shoto appears to be getting angry after hearing soba was added to the everything at the cafeteria for him by Endeavor, he calms down after seeing his soba again and goes back to slurping his noodles, causing Katsuki to shoot him a repulsed glance before grabbing more hot sauce.
- Part 4: When Katsuki and Izuku are fighting again, Shoto asks why they fight so much and that he thought childhood friends are supposed to act more like friends. Katsuki's face twitches and contorts and he says: "What? As if you’re s’posed to get along just cuz you’ve known someone awhile ... ? Then how d’you explain you and dear daddy, huh?”. This makes Shoto stop and think and he ends up admitting Katsuki is right, after all, him and Izuku are friends. This prompts Izuku to be touched and Katsuki to yell at them that that buddy-buddy crap makes him sick so to leave him out of it.
- Part 4: The day after the cafeteria conversation, Shoto runs into Izuku and Katsuki at a shrine at their lunch break and asks if they are getting along now, since they're standing side by side. Katsuki yells at him that he'll blast the teeth out of Shoto's mouth if he says something that disgusting again, while he gets goosebumps at the thought of getting along with Izuku. After Izuku gets a call from one of the sidekicks and starts running because they want them back, he yells at Shoto and Katsuki that they want them back and the two of them start running as well.
- Part 5 (Hot pot party): After the boys of class 1-A and class 1-B have a sauna endurance battle and Shoto is put in the middle to heat up the bath, Katsuki calls him half 'n' half and tells him to kick up the temperature a notch. Shoto asks if he's sure and complies. A bit later, Shoto suddenly slumps over and starts producing ice and while most of the boys are grateful, Katsuki asks what is with the cold shoulder, calling him half 'n' half again. Shoto continues even when it gets too cold and Katsuki attempts to stand and says: “All right, you ... Enough of this crap!"
- Katsuki complains about the team he's on and while Shoto and Katsuki are not facing each other initially, Shoto says: "We might get partnered too." and looks back at Katsuki, who also looks back at Shoto and says: "Spare me." with a smile on his face.
- During on of the missions, Shoto, Katsuki, Camie and Eijiro are paired together. TodoBaku don't interact by themselves, but Katsuki was the one who was frustrated by Shoto becoming the center after winning the teacup ride and Camie's illusion of Katsuki had his hand on illusion's Shoto's shoulder in a moment of comfort.
- In the drawing for Volume 2, Shoto and Katsuki are one of the guys who are dressed in a cheerleading costume. Shoto, Denki and Rikido are trying to make sure he stays/doesn't blow the thing, Shoto is pulling on Katsuki's top, which kind of chokes him.
- When the class has a picnic, Shoto and Katsuki are seen to be sitting together, just the 2 of them, although they're not looking at each other. They're not fighting though, they're just quietly sitting together.
- During the baseball game, Katsuki says for Shoto to move aside, who's by the first base, however Shoto makes him slip on his ice and Katsuki crashes.
- When Shoto and Katsuki were paired to be the daily duty officers, Katsuki says that they still need a grudge match to settle things. Shoto says that Katsuki just won, Katsuki pushed Shoto into a wall and says he knows he didn't fight seriously, to which Shoto responds that he did. Katsuki says he's a liar and then Jirou suddenly says: "Was it all just a game to you?!" and follows up with: "No! I would never toy with your emotions... Now kiss me, you fool!" as a dub for their conversation. Katsuki yells that he'll murder whoever said that, while Jirou hides after a wall. A bit later when Katsuki leaves, Shoto asks about the daily duty journal and Katsuki replies he's already done it. Shoto looks in the journal and sees that Katsuki even added the cleaning notes and the amount of detail they have. Shoto then thinks: "What a funny guy." and Katsuki earns some brownie points in Shoto's eyes for that.
- After getting more offers than Katsuki, Katsuki says he won't lose to Shoto a second time, however Shoto says it's probably because of his father. Katsuki pulls on Shoto's tie and asks what he has to do with this, Shoto says it's obviously because of him, Katsuki denies this and says that Shoto always makes everything about him, when he should be focusing on Katsuki instead, Shoto says he knows that, Katsuki demands Shoto to pay attention to him, Shoto says he is, while Jirou is behind a corner, filming everything and planning on sending it to everyone after some heavy editing.
- When the class goes to a hero themed amusement park, Shoto puts an All Might headband on Katsuki, who only notices this later.
- When the class turns into animals, except Katsuki, Shoto turns into a koala and clings to Katsuki. Katsuki fails to get him off because of Shoto's death grip. Kirishima, who has turned into a dog, sees this and gets jealous. He bites Shoto and Katsuki punches him on the head and yells at him. Throughout Katsuki's altercations with the animals that used to be class 1-A, Shoto continues clinging onto him.
- After many classmates are locked up under the kotatsu, Shoto says he has a plan to get them out, but he needs Katsuki's help, who refuses. However after being called an idiot by the ones under it and being unable to touch them due to the kotatsu being steel-reinforced and fireproof, he cooperates with Shoto's plan. Together they raise the heat in the room to smoke the others out.
- Katsuki, Shoto and Monoma were paired up for the mixed missions with class 1-B and Monoma refuses to help, Katsuki says: "Whatever! Do your own thing! C'mon Half 'n' Half!". Katsuki continues to instruct Shoto what to do and together they do the assignment without Monoma. When Katsuki and Monoma fight, Shoto decides to test out the tip he got from Izuku, by dawdling he gets Katsuki motivated and Monoma as well. They scored higher than any other team.
- Shoto and Katsuki are requested to go help at a small town event together. Katsuki complains about going, while Shoto replies that he's actually grateful for the opportunity, Katsuki says he just hates small town festivals. Shoto says that Katsuki got picked to do it because Aizawa doesn't want him to end up treating others like they're beneath him, like what Katsuki does now. At the festival, Shoto and Katsuki are put into chicken costumes and Shoto says they're ready to work hard, to which Katsuki replies that he should speak for himself. When Shoto asks how the chicken dance goes, Katsuki is surprised asks why he's so into this, Shoto says since they're not at school, Katsuki needs to watch his damn manners. After Shoto scares one of the children, Katsuki yells at Shoto to at least make an effort, which Shoto says is easier said than done. Katsuki is surprised again and asks if Shoto's crying. When Shoto changes his costume, the owner tries to convince Shoto to not do this and tells to Katsuki to help him convince Shoto. After the festival is done, Shoto apologizes to Katsuki for getting him more involved, Katsuki says what's done is done. Shoto explains his reasons, however Katsuki is distracted by Iida, Ochako and Izuku who saw them.
TodoBaku is not as popular as BakuDeku, TodoDeku and KiriBaku, however it is still one of the more popular ships in the fandom and has a loyal fanbase. TodoBaku is Shoto's 2nd most popular ship and Katsuki's 3rd most popular ship on AO3, they're the 5th most popular ship under the My Hero Academia tag in AO3. In Japan TodoBaku is the 3rd most popular ship, which is more popular than KiriBaku (4th place).
In fan fiction they are quite often aged up and shown as pro heroes (mostly with them already being in an established relationship). Alternate universes such as a no quirk one and the fantasy setting one are quite popular as well. Neither of them being the best at communication means their fics also includes angst quite often, although fluff is still more popular. KiriDeku, IzuOcha and MomoJirou are featured as side pairings quite often. Sometimes fans ship TodoBaku together with Izuku, making it the polyship TodoBakuDeku.
- Main article: TodoBaku/Gallery
- KiriTodoBaku refers to the ship between Eijiro Kirishima, Shoto Todoroki, and Katsuki Bakugou
- TodoBakuKiriDeku refers to the ship between Izuku Midoriya, Shoto Todoroki, Katsuki Bakugou, and Eijiro Kirishima
- TodoBakuDeku refers to the ship between Izuku Midoriya, Shoto Todoroki, and Katsuki Bakugou
- TodoMomoBaku refers to the ship between Momo Yaoyorozu, Shoto Todoroki, and Katsuki Bakugou
- TodoKacchako refers to the ship between Shoto Todoroki, Katsuki Bakugou and Ochako Uraraka