Katsuki Bakugo is an important supporting character in My Hero Academia. He was introduced as a hot-tempered and arrogant person who was proud of his quirk and looked down on others. Not only that, but he also became a bully, being especially harsh on Izuku Midoriya. Despite being extremely talented, he was initially shown as someone who didn't have the patience or quality to become a pro hero. However, the series has since focused on his character development a lot.
Looking back to the time when Bakugo was first introduced, there are many things that have changed about him. Instead of being completely self-centered, he worries about others as well. He believes in the strength of his classmates, and despite having a harsh tongue, he has mellowed out a lot since the start of the series. He has a strong sense of justice and won't bow down to power even if it means putting himself at risk.
What Was the Major Turning Point in Bakugo's Life?
The incident that impacted Bakugo the most was when he was kidnapped by the League of Villains during the "Forest Training Camp" arc. Following his kidnapping, the "Hideout Raid" arc started, in which All Might battled against All For One. The battle resulted in All For One's loss, but at the cost of All Might losing all his powers and retiring as a Pro Hero. Bakugo was consumed with the guilt of knowing that the hero he had admired since childhood lost all his powers because of him.
Since then, the changes in his personality have been clearly visible. It was the first time he realized that he can lack power as well. He recognizes that if he had been stronger, he wouldn't have been kidnapped and All Might would still be the Symbol of Peace. It was rather enlightening to see such a prideful and arrogant character acknowledge his weakness. However, Bakugo's change doesn't happen in the span of one or two episodes. Rather, the series gradually builds his character over a prolonged period.
Bakugo Stopped Looking Down on Others
Previously, whenever Bakugo used to fight with others, he would always look down on them and try to bring them down with his words before actually getting into the fight. He was especially skilled at angering his opponents, who would then underestimate him because of his age, only to realize how different their skills were. However, ever since Bakugo's personality changed, he has taken a different approach. After his defeat and kidnapping by the League of Villains, he suffered another major setback when he failed to get the provisional license, unlike the rest of his classmates.
As a result, he had to take up remedial courses along with Shoto, who also failed. During the final class, the students were asked to take care of a class of notorious kindergartners. When one arrogant kid demeaned the other students, Bakugo told him that if he always looked down on others, he would never understand his own weaknesses. Rather than just explaining this to the kid, it seemed more like Bakugo was speaking from personal experience, probably seeing in that child his past self.
From Being a Bully to Someone Who Protects
Bakugo tries to protect others even at the risk of getting hurt. In the "Forest Training" arc when Bakugo was being kidnapped, Midoriya rushed toward him frantically. At that moment, the first thing that came to Bakugo's mind was to warn his friend to stay back lest he get hurt. Moreover, in the "Joint Training" arc, Bakugo assured his teammates to follow his instructions and that if they were to face danger, he would protect them.
This is exactly what happened; when Jirou was about to get attacked, Bakugo rushed in front of her and launched a deadly explosion toward his opponent. It was surprising for not only his team but the rest of his classmates, including Izuku and All Might. Bakugo's act of saving Jirou from the opponent not only allowed his team to win the round but also earned his teammates' respect. Even in the latest season, during the "Paramount War" arc, Bakugo protected Deku at the expense of his own life. He holds the ideals of a true hero -- one who will stop at nothing to triumph over evil and save people.
Bakugo Now Has the Qualities of a True Hero
Bakugo strives to be just like All Might and sees him as his idol. Even when he was captured by the League of Villains, who offered him a place within their ranks, Bakugo refused without a second thought. He even made fun of the league for coming up with such an idiotic plan and wasting their time attempting to get him on their side, as it's something he would never consider. Despite his anger issues, Bakugo is an extremely honest person. He always speaks his mind and doesn't lie, regardless of the outcome.
When he was kidnapped by the league, Bakugo could have agreed with them on the surface, knowing how risky it was. However, despite the danger, he refused to yield. Not only that, but he can figure out in an instant if someone is being honest or not. Just before their provisional license exam, the students of class 1-A were greeted by an over-friendly Yo Shindo from Ketsubutsu Academy. Everyone was delighted to meet such an outgoing person except Bakugo who knew instantly that the look in Shindo's eyes didn't match his words. Being an excellent judge of character is an important trait for a pro hero. The world of superhumans is full of deception and deceit, and in such a world, Bakugo's intuition will prevent him from being fooled by others.
Unlike the first season, when Bakugo would always rush into battle solo, he has gradually learned to work with others, albeit only when he is the undisputed leader of the group. During the "Joint Training" arc, Bakugo assumed the role of the team's leader and led them to victory. He knew the strengths and weaknesses of his teammates and took the best course of action to ensure their win. Bakugo's team trusted him and followed his every direction, which proves that he has great leadership skills and the ability to think carefully in times of crisis.