My Hero Academia: How Much Has Bakugo Changed Since Season 1?

gamerant.com:

Katsuki Bakugou is an extraordinary student with a short temper. This boy doesn't need to be told he's good, he already knows. Bakugou has enough confidence for everyone plus some more, but he wasn't hero material at first. Having a great quirk isn't the only thing one needs to be a good hero, and Bakugo served as a perfect example of that early on in the series.

Bakugou's first appearance in season one made him out to be a bully, specifically, Izuku Midoriya's bully. Bakugo often berated Deku, telling him that he had no chance of being a hero because he had no quirk. As the show progressed, fans saw that he was easily angered, felt himself above everyone else, and had none of the social qualities needed to be a hero. Gradually fans started to notice changes to Bakugou as the series progressed.

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Throughout his entire life, Bakugou was praised for his quirk. Understandably, since his quirk allows him to do distant and close-range attacks and launch himself into the air, the praise helped with his confidence but created a huge ego that was easily bruised. Bakugou needed to learn that he would fail and that his quirk wasn't always enough. Sadly he had to learn this the hard way.

After being kidnaped by the League of Villains, Bakugou was a bit more distant, probably because he wasn't able to free himself. He had to rely on others while All-Might lost his powers to save him. Following this, Bakugou also failed his provisional licensing exam, adding to his failures.

These events made Bakugou adapt and accept that saving people was part of being a hero. He's even started prioritizing it over fighting the villains. Bakugou has also started to include others in his plans instead of just dragging