Izuku bit the bottom of his cheek so hard when he realized that the Villain was hurting Aizawa-sensei as he held him by the elbow. He forcefully controlled his impulses and tried to calm his mind. He wanted so badly to reach out and calm the teacher and take away his hurt. The pain and fluctuation in his Aura was a show of how painful it must have been. He wanted to slam a fist in Shigaraki's face!
It was only when Aizawa-sensei broke away from the Villain that he could make his move. He couldn't make a move earlier because he was afraid that he wouldn't be able to control his strength when using One for All. No matter how good his control was during training, it was training and not a real battle. He couldn't say with certainty that he wouldn't hurt Aizawa-sensei.
"Your Quirk," the Villain rasped. His voice could send shivers up countless people's spines. "It's not good in long, group battles, right? It's kind of different from your usual work. You specialize in sneak attacks! Yet you jumped into the battle, hoping to make the kids—"
It was at this moment when Izuku finally stepped into the battle, the Villain's Aura showed that he was completely focused on Aizawa-sensei as his mind obsessively latched onto the teacher's presence. If Izuku was able to read his mind, he was sure that the Villain would have nothing but Aizawa-sensei in his sights as everything else fled to the back of his mind.
With the Nomu neutralised, Izuku could safely make a move. Izuku charged up ten percent of One for All, punching towards the Villain's blind spot. He aimed to neutralize and perhaps injure, but never kill. A Hero could never kill, or they wouldn't be called a Hero.
Almost like he had eyes on the back of his head, Shigaraki dodged to the side at the last moment, dodging the punch, but not the shrapnel and rubble that flew towards him.
"Ugh!" Shigaraki said in his raspy voice. He hunched over, clutching at his abdomen. The wound there was bleeding sluggishly as a piece of sharp shrapnel pierced him. "Hehe, and you call yourself a Hero," he said, his cracked lips spreading into a creepy grin.
Izuku took a breath to calm himself as he let the mocking words wash over him, not taking any of them to heart. Shigaraki's attention switched over from Aizawa-sensei to himself, and he couldn't lie to say he wasn't unnerved to be on the other end of that gaze.
Silently, Aizawa and Izuku moved in tangent to attack the Villain. After exchanging numerous blows, Shigaraki snapped as his impatience overtook him.
"Nomu!" he cried, frantically dodging the two's blows.
Nomu didn't make a sound or movement.
A bad feeling creeping up, Shigaraki kicked Aizawa away for some breathing space as he shouted again. "NOMU!"
The Nomu made no move. By now, the Villain was aware that something was wrong.
Shigaraki snarled, rapidly retreating. It looked like he would have no chance to kill All Might today. Nomu wasn't responding to him, meaning it was time to grab it and retreat for the time being.
"Kurogiri!" Shigaraki screamed. "We're leaving!"
Kurogiri indeed warped himself to where they were, behind Shigaraki. Izuku and Kurogiri's eyes met for the fraction of a second as they developed an understanding.
Shigaraki turned around, preparing to dive into Kurogiri's portal. Kurogiri opened what seemed like a portal, but instead created a void around the space to prevent him from moving.
Izuku's eyes glowed. He knew he hadn't made the wrong decision to trust Kurogiri.
Stunned, Shigaraki slammed a fist onto the dark screen in front of him. "What are you doing! Are you betraying the League?!" he shouted, his anger exploding. Kurogiri was ruining his game! He was a filthy traitor that didn't deserve to live! If he knew this would happen, he would have had the other killed a long time ago instead of keeping him around! He would have asked Master to strip him of his Quirk and give it to himself instead! He screamed and raged in anger.
Izuku stared at the Villain contained inside the space, watching as he mouthed explicit words and phrases.
Aizawa instantly went into a stance that could be both offensive and defensive, hiding Izuku behind his body. Izuku felt endless affection for his teacher at the display of protectiveness. He could tell that the man wanted to scold him and berate him for throwing himself into such a dangerous situation, but he was also grateful because he had been flagging while he exchanged blows with numerous Villains. Fighting head on really wasn't his strong suit.
"Who are you," he said tightly. If it hadn't been for trapping Shigaraki inside there, he would have gone on the offensive already. But since something told him not to, he stayed his hand for the time being.
Kurogiri's fog wavered as his emotions fluctuated before returning to calm and indifference. "I am not an enemy," he said lowly. "I wish to defect from being a Villain."
Aizawa's brows furrowed as he kept up his vigilance. Izuku stepped out from behind him, ignoring his teacher's frown. "Kurogiri made a deal with me, sensei. He was the Villain's escape route, but he doesn't want to work with them anymore."
Aizwaa's frown deepened as he couldn't quite make sense of it. Since when had a Villain suddenly defected in the middle of a battle and turn over a new leaf? However, his gut told him that the Villain in front of him really was planning on defecting.
He sighed. Problem child. Only he would be able to convert a Villain into a friend.
While Aizawa kept a wary eye on Kurogiri, Izuku took care of the other minor Villains in the area, knocking them unconscious.
Just as Aizawa was about to split them up and go rescue the rest of the class, All Might made his appearance.
"Fear not. For I am here," came All Might's resounding voice. It didn't sound as bright as usual. Instead, it sounded dangerous and foreboding. His eyes scanned around but realized that the threat had already been neutralized. He inwardly heaved a sigh of relief as the anger faded slightly.
Izuku looked at him with worried eyes. All Might wasn't in the best of moods right now. The anger that he was feeling was very strong, though it had lessened slightly after seeing that the Villains were unconscious on the ground and one was trapped in some sort of space.
"I had a bad feeling, so I cut short my talk with the principal, but it looks like everything's under control," he said.
It was at this moment when Izuku realized that the anger he was feeling wasn't entirely directed at the Villains, but also partially himself. When his mind made the connection, the violent fluctuations in his Aura made sense. Toshi must be feeling angry at himself for using so much of his time up and not leaving enough so that he could oversee the training for class 1-A instead of having to arrive here at the last minute.
Izuku desperately wanted to take him aside and tell him it wasn't his fault, but he couldn't do it at this moment. It seemed like the day he had first entered Toshi's room that day in the hospital, when he was filled with depression. He was worried that it was making its reappearance.
The green-haired teen grit his teeth, silently resolving to talk it out with the other man. He had to speed up his plans to try and help All Might. He was so emotionally disturbed that the ever-present and trademark smile of his was wiped off his face. Only Izuku knew what emotional turmoil he was going through right now. His heart went out to his mentor.
Before he could stop him, All Might left explosively, returning and leaving again each time, dropping off Villains and classmates alike.
The moment he spotted Kacchan, Izuku's heart soared. The two of them hugged in relief that the other wasn't hurt. Izuku melted as the worry that he had been ignoring was finally put to rest.
Suddenly, Izuku realized that All Might was directing angry eyes at Kurogiri. Izuku hurriedly broke out of his embrace with Kacchan as he dashed to block All Might, holding out his arms.
"Wait!" Izuku said, his mind whirling frantically. "Kurogiri's on our side now."
"How do you know he's really on our side?" asked Yaoyorozu.
"I adopted him," he said with a straight face.