Chapter Text
Izuku and Katsuki were one hell of a duo. Being together since diapers tends to make people quite close. Sure, they had a rough patch in middle school, but now, during their time in high school, Izuku had forgiven Katsuki, and the two were best friends. Well—Izuku admits he might like Kacchan a little more than that. He won’t burden the blonde with that knowledge, though. He wouldn’t dare risk ruining their relationship when it’s stronger than ever.
“Kacchan?”, Izuku asks to the empty woods. The two of them liked to spend time here together. It was away from the rest of the world, and a nice private spot where they had been building a treehouse together at. There wasn’t anything in it yet, having just finished it. It was probably illegal to do such a thing, but nobody ever comes to their spot anyway. Izuku takes out his cellphone, making sure he didn’t imagine Kacchan asking him to meet up here to read the new Superhero comic they’d been waiting for in their newly acquired treehouse. It was 10pm so it was dark, but the both of them had insomnia and couldn’t sleep for shit anyway. Kacchan used to have a good sleeping schedule but that was before the incident in high school. He frowns imagining the scars littering the boy’s body.
Izuku feels a sudden ping of anxiousness ride through his nervous system like a lightning bolt skipping down his spine. He started to become incredibly worried after a few minutes of looking around. He was a bit overprotective of his best friend, sue him. “Kacchan?!”, he yells out louder. There’s no response and he’s about to head home when abruptly he hears screaming. No, not just screaming. Kacchan screaming.
Before Izuku can even think, he springs into action. His body moved on its own. Running toward the sound, he stops himself from vomiting at the sight. Kacchan is on the floor—passed out and covered in dark red blood. Above him, a man—no, not a man—turns to Izuku. To his horror, the man’s body becomes sludge as he chuckles and walks toward him. The eyes stand out to Izuku, the number 10 etched into one of them. “Gee, I sure am lucky today. Don’t even have to find any dinner, it just runs up to me”, the sludge smirks. Before he can process the words said to him, the slimy creature strikes.
Izuku responds to the attack by jumping out of the way, hitting the ground painfully hard. Yep, his shoulder’s gonna need to be checked out later. Turning back to his somewhat-humanoid form, the being laughs and mocks him. “No need to resist kid, don’t fight battles that you can’t wi-“, the sludge on the face of the creature turns from resembling a smirk to a look of horror. “N-NO!”, the creature exclaims as his head hit’s the ground. Standing behind him is a man with a slick black sword in hand. “YOU HASHIRA SCUM, YOU’LL REGRET THIS!” the face screams until eventually fading to ash.
Before Izuku can thank the stranger, the man makes his way to Kacchan in the blink of an eye. Izuku reacts faster than he ever had before, grabbing a rock as the man lifts his sword in preparation to kill his unconscious best friend. Throwing the rock as hard as possible, he aims towards the head of black hair. The man turns around and catches the stone before it can hit him and pierces Izuku with a fierce glare. “What do you think you’re doi-”
“KACCHAN!” Izuku runs over to the boy, ignoring the older man. “Kacchan, please wake up!” Izuku cries and finally allows the tears to stream down his face. His friend looks awfully pale. He checks his pulse and to his surprise, finds something.
“LEAVE KACCHAN ALONE!” Izuku turns around and screams at the stranger. The man has the nerve to look annoyed. “I WON’T LET YOU HURT HIM!” he yells, holding his arms out in a protective move in front of Katsuki. The man before him sighs and puts his sword back in its hilt.
“Is this…person… someone you know?”, he hesitantly asks the boy protecting the demon’s body. Aizawa’s special eyesight had immediately caught onto the demonic aura surrounding the boy. He moved towards the two just a little bit so he would be ready to strike if the demon woke up.
The crying high schooler silently nods. “Kacchan is my best friend”, he replies solemnly. “And he’s gonna be fine, so you can go now”, the boys demeanor shifts and he glares at the hashira.
“I’m afraid I can’t do that kid”, Aizawa responds eyeing the duo. He sighs once again; there’s a reason he became a demon slayer and not a therapist. He still feels for the kid though, this situation is sure to traumatize him for the rest of his life.
“Who even are you!?”, the boy yells back frustrated. Aizawa gets down on his knee so he could be face level with the teenager.
“I am a demon slayer”, Aizawa responds —stoic. “And I know this is upsetting to hear but your friend”, he points at Katsuki, “has become a demon.”
“Well you have no right to hurt my Kacch-”, Izuku starts but is cut off by a growl coming from behind him. The urge to turn around and ask if his friend is ok is strong but his attention is focused on the man in front of him pulling his sword back out from its home on his back. Izuku, overcome with anger, jumps and tackles the man to the floor. The man, surprised, groans and pushes the boy away. His focus back on the demon, now sitting up. The shiny red eyes stare back at Aizawa, and he hesitates for the first time in a long time. Damn him and his soft spot for children. Izuku tries to attack him again and he simply shrugs the boy off. As he does so, the demon child moves so fast his eyes don’t even track him as he takes his place behind the boy. Aizawa reaches his sword up, ready to swing.
“Ku!”, the demon exclaims and hugs the boy from behind. The hashira raises an eyebrow at the display of affection and lowers his sword hesitantly. He wouldn’t be able to cut off the demon’s neck when it’s so close to the human boys’. He’s also extremely confused, having completely expected the demon boy to wake up attacking them, hungry for blood. The demon looks up and glares at Aizawa, holding the human in his arms and growling.
“WAH-chan?!?!”, the boy screams as Kacchan wraps him in his arms. He glances over his shoulder and Kacchan looks at him back. His eyes are perfectly normal, and he appears to be completely fine. The man must’ve been lying when he called Kacchan a demon.
Before Izuku can do or say anything else, there’s an explosion and he’s being picked up. The lungful of smoke makes him pass out. The hashira, against his training and better judgement, doesn’t follow behind.