Katsuki Bakugo/Relationships

Izuku Midoriya
Katsuki and Izuku were playmates during their childhood. However once Katsuki learned Izuku didn't have a Quirk while he himself has manifested a powerful one, he had since always considered the latter as a hindrance in his path to becoming the greatest hero, bullying Izuku for more than ten years. Although he felt superior to Izuku, there are times where he feels that Izuku was making fun of him, such as when Izuku saved him or due to Katsuki thinking Izuku is "hiding the fact that he had a Quirk all this time".

After his loss to Izuku in the Battle Trial, Katsuki sees Izuku as his arch rival and has always shown hostility towards Izuku whenever he interacts with him. Katsuki's antagonism towards Izuku only intensified after seeing Izuku improved on his use of Quirk. His antagonism is so great that even when teamed up with Izuku, Katsuki ignored whatever he suggested and went as far as to attack him for trying to help him and stated that he doesn't need his help. However, after Katsuki stated to All Might he would rather lose than accept help from others, Izuku punched him in the face stating he's not the type to just give up like that. Though reluctant, Katsuki got the message and finally worked together with Izuku and willingly protected him from All Might so he could get to the finish line.

Even still, Katsuki still is antagonistic towards him. He refused his help when the League of Villains was targeting him by telling Izuku to stay back when he was captured. He did this not for Izuku's own safety but because Katsuki still disliked receiving assistance from Izuku. Even after being saved by Izuku, Katsuki still, out of spite, refuses to thank him.

Eijirou Kirishima
Katsuki seems to get along well with Kirishima, despite their differing personalities. Eijirou looks up to Katsuki's explosive attitude, often interpreting his actions as manly, something Eijirou appears to highly value. Although, he's not above getting frustrated with Katsuki's tendencies, as seen when Eijirou tried to get him to cool off after Monoma insulted them during the cavalry battle. Although Katsuki at first didn't give Eijirou much attention, he seems to appreciate their Quirks' compatibility with each other, as he accepted Ejirou's proposal to form a team during the Human Cavalry Battle. However, at the beginning of the Sports Festival, Katsuki called Eijirou "hedgehog hair" (despite having spiky hair himself), which bothered Eijirou. Overall, Katsuki gets along with Eijirou, and as such Eijirou is the only person in Class 1-A Katsuki actually respects and would go as far as calling Eijirou a friend. As noted by Izuku, Eijirou is the only one in their class who can call out to help Katsuki without hurting Katsuki's pride, which was proven true and shows that Katsuki indeed does view Eijirou as a friend.

Shouto Todoroki
Katsuki sees Shouto as another rival and someone that he needs to defeat to become Number One. When Shouto and Izuku talked to each other after the Human Cavalry Battle, Katsuki secretly overheard Shouto's backstory, with a seemingly surprised expression on his face after hearing it. Despite hearing Shouto's tragic backstory, Katsuki showed no sympathy towards Shouto and even said that he didn't care about Shouto's problems or feelings. After their battle in the Sports Festival, Katsuki despised Shouto due to him not giving him a battle worthy enough of being called Number One. Katsuki's anger at Shouto caused him to be fully restrained during the closing ceremony of the Sports Festival so that he didn't release his fury onto Shouto.

However, Katsuki seems to have let go of his grudge as the two were seen having a normal conversation during their training at the lodge cabin. In other words, Katsuki and Shouto appear to be neutral with each other.

Ochako Uraraka
Katsuki doesn't bother to interact with Ochako, most likely due to her being friends with Izuku. They first interact during the Sports Festival tournament when they have to face each other in the first round. Katsuki, in his own way, had offered Ochako the chance to withdraw since would show her no mercy even if she is a girl. Before the end of their match, Katsuki used her last name before finishing her off, indicating that Katsuki respects Ochako's perseverance (as he usually doesn't use peoples' names). He even went out of his way to say that Ochako wasn't fragile, even when his classmates said that she was. Ochako is the only girl Katsuki actually acknowledges. His nickname for her is "round face."

All Might
Similarly to Izuku and Shouto, Katsuki idolized All Might as a child. While very little of this respect and admiration remains in present time, it seemed to have a strong impact on Katsuki's belief in what a hero should be. Despite Katsuki's aggressive nature, All Might repeatedly attempts to guide him whenever possible. Although his advice often fallen on deaf ears and All Might is often unsettled by Katsuki's behavior, be it his aggression or his reckless drive.

Unfortunately, despite his past admiration for the renowned hero, Katsuki does not hesitate to either insult or challenge All Might to a fight, refusing to run away when he fought him, only to suffer a humiliating defeat, just as Izuku stated. He was also angry and embarrassed that he had to be saved by All Might when he was kidnapped and even refused to thank him. Despite his antagonistic attitude towards his former idol, Katsuki did show concern when Sensei attacked him, showing that he at least somewhat care for him. After learning of his true form, he still believed in All Might's ability to be a hero and refused to lose his faith in him. However, with the latter in retirement, Katsuki seems to have gotten a clue about All Might's relationship with Izuku, going as far as to ask him about what he is to him. Even still, Katsuki did thank All Might for saving him from the League of Villains.

Katsuki's Mother
Katsuki doesn't seem to respect his mother, as he insulted and threatened her in front of his teachers. However, these threats are more like his usual, childish reactions to everything and not genuine.

His mother has a similar attitude towards her son, as she often yells back at him and insults him too. She is aware of her son's terrible behavior and disapproves of it. She blames on the fact that her son has a strong quirk and receives a lot of praise for it, which seems to make Katsuki angry about her statements. Katsuki's mother approves of her son going to Yuuei though, as she believes the school will see him for who he truly is.

All Might also comments that their family is the most dysfunctional one he has ever seen, although he only thinks it to himself instead of saying anything aloud.