Bakugou stormed off to his dorm room. He was having a bad day, like anyone, but he was much angrier than usual and ignored everyone. Including Kay. This made her worried, so she went and checked on him, wanting him to be okay.

Kay knocked on his door gently, waiting for him to answer. There was a moment of silence, but soon, she heard Bakugou stomp over to the door, opening the door. "What the hell do you want?" he asked harshly, staring down at her. "A...are you okay, Katsuki? You seem like you're having a bad day," Kay told him, which made him scoff at her, his eyes narrowing on her. "Yeah, no shit Sherlock, did you figure that out all on your own?" 

"Well...if you need to talk-" 

"Oh fuck off with that." 

Bakugou went to close the door, but Kay gently put her hand on his face, caressing his cheek. "Katsuki, I'm your girlfriend, I promise you-" Bakugou suddenly grabbed her arm tightly, glaring at her. "Did you not hear what I said?! I said fuck off! Can you just not listen or something?! I don't want to be around anyone, especially not some goody touches brat who thinks she knows how to fix everyone!" As he yelled, his grip got tighter, and Kay could feel warmth from where he was holding. 

"Kats-" 

"I don't need your help, I don't give a damn what you think. You're my girlfriend, so what? Does that mean you can just come and annoy me when you want?! I don't want to be around you right now, so-" 

"Ow! I-I'm sorry please just let me go!" 

"What?! Now you don't want to be near me?! Did you finally get it through your thick skull that you're not just some hero that can make things better? Is that it?!" He yelled, before he saw his grip on her...and saw smoke coming from his hand. Kay had been struggling to get out of his grip for a while now...

Bakugou's eyes widened, and let her go, making Kay fall back a bit, holding her arm. There was a burn mark where he had been gripping her. Kay teared up a bit, holding her arm close. "I-I'm sorry, I just wanted to help...I'm sorry..." Kay whispered, looking up at Bakugou with fear-filled eyes. The look in her eyes made Bakugou's heartbreak. Out of everyone there...Kay was the last person he wanted to hurt. 

"Kay...I...I'm so sorry...I didn't..." Bakugou went to take a step closer to her, but as he did, Kay flinched a bit. He started to tear up, realizing how much she was afraid of him now. "Damnit...I'm sorry...fuck!" He then turned back into his room, slammed the door shut, and fell to the ground crying. 

"Not her...why did I hurt her?! She just wanted to help me! Damnit!!" 

After a few hours, there was another knock on Bakugou's door. "Fuck off!" Bakugou yelled. "Get out here. Now." 

The voice belonged to Koy. 

Bakugou's eyes widened a bit, hearing how upset he sounded. He took a deep breath, before opening the door. Koy was standing there, looking quite pissed. Whereas Bakugou looked like he had been crying for hours, and his room was a mess. "So...want to explain why my sister is hurt?" Koy asked, his arms crossed. "I...I didn't mean to...I swear, Koy you know how much I love her, I-" 

"Do you? The way you yelled at her just because she was worried about you, and you burned her arm badly, giving her 2nd-degree burns. Is that what people who love others do?" 

"Koy, please...I was having a shitty day..." 

"Oh, so because you felt terrible means you can hurt her now?" 

"No! That's not what I'm saying! I wasn't thinking straight! I hate that I hurt her and made her afraid...She matters to me, to see her look at me with fear broke my heart..." 

"Still, you hurt her...and made her feel terrified. I can't forgive you, there's only one thing we can do..." 

Bakugou lowered his head, letting out a shaky breath. "...fine, we'll settle this..." 

The two walked outside, the others watching them. "Where are they going?" Mina asked as she put an ice pack on Kay's arm. "T...oh no..." Kay said, going to run after them, but Kirishima stopped. "Hey, you need to rest, you got burned pretty bad," he said, looking at her concerned. "P-please, Eijiro...I don't want them getting hurt..." Kay pleaded, almost on the verge of tears. Kirishima sighs, before nodding. "Alright...but I'm coming with." 

The two went out to find Koy and Bakugou, only to hear the sounds of punching and grunting. They followed the sounds and found the two in a fistfight. Bakugou punched Koy in the face, slightly knocking him back, but Koy then quickly went and punched him in the gut. It seemed they had already been fighting for a while in the short amount of time it took Kay and Kirishima to find them. 

"G-guys stop!" Kay shouted, going and grabbing Koy's arm, and Kirishima pulled Bakugou back. "Calm down! There's no need for this!" he yelled at the two. "Get off!" Bakugou yelled, trying to get free as Kay held Koy's arm tightly. "Kay, just let us settle this..." 

"N-no! You don't need to fight him over this!" 

"He fucking hurt you! After everything with Mom, you're really going to let this slide?" 

"It was an accident, Koy, he didn't mean-" 

"Damnit, Kay! You can't protect him whenever he does shit like this! I get he's our best friend, but if you just keep letting him hurt you over and over-" 

"I WON'T!!" 

Bakugou yelled, tears rolling down his eyes. "I hate that I hurt her! That's why I'm barely fighting! Because I deserve to get beaten down! I hurt the one person who actually makes me happy! I swear I would never hurt her again...I don't want to see that fearful expression on her face, it breaks my heart, knowing the only girl that's loved me...is afraid of me, and probably wants nothing to do with me...so just let Koy beat the shit out of me for her!" 

It was silent for a moment, the four of them just standing there. After a while, Kay let Koy go, and walked up to Bakugou, gently cupping his face with her hands, wiping his tears. "Katsuki...I love you, and that will never change, it scared me a bit when you burned me...but I'm not afraid of you, because I know you'd never hurt me on purpose. You don't need to get beat up, it's okay..." Kirishima let Bakugou go, giving them a moment. Bakugou gently held one of Kay's hands to his cheek, still crying. "Damnit...you're too good for me...anyone else would've walked away-" 

"I'm not anyone else. I will always be there and help you when you need it, even if you try to push me away, I want to be by your side. I love you so much." 

"...I love you too...I don't deserve your love..." 

Kay gently kissed him, making Bakugou wrap his arms around her tightly, just holding her. "I promise I'll never hurt you again...I swear..." 

"I know you won't, I forgive you..."