My Hero Academia's fourth season was explosive, pushing the story to new heights as Izuku Midoriya faced new challenges both internal and external. Even with All For One defeated, evil was still gaining ground as the crime boss named Overhaul was ready to make his move. There was no time to waste.
Season 3's ending teased Overhaul's arrival. Once the Shie Hassaikai Arc began, a handful of main characters stepped up to face this threat, taking an intense but rich opportunity to grow as people and as heroes. Which five particular characters saw the most growth during this arc's trial by fire?
Izuku Midoriya, Who Learned Responsibility
Izuku Midoriya's goal was clear from the very start: to train hard, learn how to wield One For All, and replace All Might as the symbol of peace. But that's easy to say when he's within the safe confines of U.A. or fighting villains with only his own life at stake. During the Shie Hassaikai Arc, Izuku and Mirio Togata met the young Eri, and they were heartbroken upon learning the truth of Eri's treatment at the hands of Overhaul. They had a chance to save her early on but squandered it.
Now Izuku is taking responsibility for Eri's safety, and he and Mirio risked their lives and pushed themselves to new heights to rescue her no matter what. This time Izuku was fighting purely for someone else's sake, learning the true reason he was given One For All. This Quirk's potential is realized when the user is ready to lay their life down for someone else's, and sure enough, Izuku took on Overhaul and defeated him (with a little help from Eri herself). Now Izuku and Mirio are like big brothers to Eri, and Izuku will be a little less self-absorbed now. He fights for others, not for his own glory.
Mirio Togata, Who Learned To Face Grief & Loss
Mirio Togata, the #1 student at U.A., seemed to have it all: a great personality, immense strength, an incredible Permeation ability, and vast experience as a trainee hero. He was like a mentor to Izuku during the Shie Hassaikai Arc, even introducing Izuku to Sir Nighteye of the Nighteye Agency. Soon enough though, Mirio faced his own challenges that nearly broke him.
Mirio, like Izuku, was ready to risk it all to rescue Eri, and he even suffered the loss of his Quirk in the effort to bring Overhaul and his gang down. However, Mirio suffered even greater loss when Sir Nighteye succumbed to his injuries in the hospital. He was reduced to tears by Nighteye's warm parting words, but found the mental fortitude to endure this loss and move on -- an important trait for any hero. The death of a comrade must not shatter the hero's resolve, and now Mirio truly understands that.
Eijiro Kirishima, Who Learned To Not Pity Himself
Izuku and Mirio weren't the only melee heroes who stepped up to fight the villains of Shie Hassaikai. Eijiro Kirishima had always felt bad about his "lame" Hardening Quirk, wondering if he was really cut out to be a hero with such an ability. He patrolled the streets with Fat Gum, a pro hero, and encountered the Quirk-suppressing drug that Overhaul was mass-producing. It was time to take the fight to Overhaul directly.
Eijiro and Fat Gum faced two Shie Hassaikai members and were on the ropes before long. Eijiro thought back to his middle school days, when Mina Ashido's bravery had inspired him to enroll at U.A., and decided that fear and self-doubt would never hold him back again. Eijiro went Plus Ultra as he turned the tables on his two Eight Bullets opponents, giving Fat Gum a chance to finish them off. Red Riot is on the scene and he's here to stay.
Eri, Who Learned To Trust Others & Herself
The young Eri was the focal point of the Shie Hassaikai Arc, since her remarkable Quirk could rewind another person's Quirk or physiology. This ability laid the groundwork for Overhaul's Quirk-suppressing darts, but poor Eri was exploited and tormented in the process. She came to fear everyone around her, including herself. Was she a monster whose sole purpose was to be used for harming others?
Eri was understandably anxious and fearful around others, even Izuku and Mirio at first. After her rescue however, she was treated with great kindness and was allowed to come out of her shell on her own. Eri was soon smiling and laughing like any child her age would, even looking up to Mirio and Izuku as big brothers during the school festival arc. Eri's dark days are over and she can now feel comfortable with herself and her Quirk, along with a new family full of people who love and respect her.
Tamaki Amajiki, Who Learned To Shine On His Own
Tamaki Amajiki is one of U.A.'s "big three" -- along with Mirio Togata and Nejire Hado -- but he hardly acts the part. In fact, Tamaki is a shy and unassertive third-year who usually lets Mirio hog the spotlight, saying he is radiant like the sun. But these boys' friendship goes back a long way, and back then, Mirio shared some kind words with his friend. One day, surely, Tamaki will actually eclipse Mirio, like he's eating the sun. A sun-eater.
Thanks to the Shie Hassaikai Arc, Tamaki is living up to Mirio's faith in him as he stood his ground against three members of the Eight Bullets all by himself. He even had his own Plus Ultra moment as he turned the tables and toppled the three villains, his shyness and self-doubts forgotten. Tamaki has incredible power and potential and has no business underestimating himself. The sun has just been eclipsed.