Katsuki knows there's something wrong with his father.
The man is too sweet towards him like he's trying to win him over, to gain his trust. He works late hours one week and stays home the next. His office is always locked. Sometimes, his mother will look at him with the eyes of a hunted animal, alone and afraid.
Some days, he can trick himself into thinking he's just a sensitive guy who just wants to help. Others, he refuses to leave his room from the paranoia.
When he manifests his quirk, his mother looks at his father with suspicion but doesn't comment. He gets his mothers quirk, with nitroglycerin instead. It isn't until years later, long after developing the missing spark that goes along with his quirk, that he discovers the other side to the coin.
He trains his quirk brutally, and his father lets him be, looking at him with strangled smiles and head pats.
When he tells him he wants to go to UA, he narrows his eyes dangerously at him, then shakes it off and gives him a sharp smile, saying that they could talk about it when he was older. His mom pulls him aside later, warns him not to mention heroes in front of his father.
His father is strange. There's something wrong with him, and it unsettles him. He knows that his eyes will become just like his mothers one day, wild and terrified.
But for now, he sits quietly next to his father, watching him stare at the TV in front of the couch while Katsuki plays with his toy cars. He has his hand on his head, patting his locks of hair, and the boy ignores the chill is his spine while taking in the peacefulness of the morning sun.
His father turns and smiles at him, soft but not quite right. His brown hair is spiky, just like his, and he hates having inherited that from him.
Katsuki gives him a toothy grin that isn't quite real either and hits his blue car with the red one in his hand.
He imagines the blue car is his father.
Mitsuki is temperamental, but nothing he can't handle. When his dad isn't home, he spends as much time he can with his mom, cooking or cleaning alongside her, or accompanying her to photo shoots.
The woman isn't gentle, but he doesn't mind. Gentle is his father, and he doesn't like him. Instead, he finds comfort in her loud yelling and the way she pulls him along. When he does something wrong, a slap will usually confirm it for him, as opposed to his father, who goes in circles to confuse him.
He doesn't like Auntie much, her soft demeanor reminiscent of his dad's, but Mom says she's nice whenever they go over, so he trusts her to some extent. Izuku is too much like his pop's, though, down to the T, and he tries his best, but sometimes he just can't be around him for long. His mother understands this, so they leave early when he's reached his breaking point. He starts putting up with it if only to give his mother a break.
Izuku starts to grow on him eventually. He understands him, knows the difference between his tough love and scorching ire. It doesn’t stop the knot in his stomach from forming whenever he asks if he’s okay, or when he gives him hugs and taps him on the shoulder, but he reminds himself that this is how Izuku lives, that he doesn’t know better. That calms him down when his mind manages to convince itself that Izuku is trying to manipulate him.
He does get the feeling his dad doesn't exactly like Izuku though, and that eggs him on. By the time he’s six, three years of repeated contact with Izuku has mellowed him out. He can stand gentle touches again, though not repeatedly, and he’s proud when he doesn’t flinch away from Auntie Inko when she ruffles his hair or hugs him.
She doesn't soothe the pain he feels when his mother powders her face in makeup to hide the bruises or in the nights he hears his mom screaming in her bedroom, stopping occasionally when his father hits her.
He hears him one night, when he's seven and on a silent trip for water. He's walking down the stairs when he hears him, voice devoid of his mock mirth. He's talking to someone on the phone, someone important.
“Kurogiri, how is the league?” He says, voice gravelly and deep. He sounds like a different person.
There's a pause, then a sigh.
“No, he's still too young. We aren't getting anything useful out of him in a while. When he's older, perhaps.”
He sounds uncharacteristically firm. The shy, pacifist persona his father has maintained is gone, and it scares him. This isn't his father. Does his mother know about this? About him?
“You know how he is. Vengeful about the death of his master to the point of irrationality,” speaks his dad. “All Might is a fool for thinking I'll hand myself over peacefully.”
That chills him. All Might? Why--
“Well, I must be going. I don't want to wake Mitsuki. I'll check in later. Villainy doesn't sleep, after all.”
True to his father's words, he doesn't sleep at all that week.
“Mom,” he says blankly, “My hands smell weird.”
He's four, waiting for his quirk to come in. His hands have been extra sweaty lately, and they constantly smell like caramel. Katsuki hates caramel.
His mom smells his hands, wrinkling her nose at the sickly sweet smell.
“Katsuki, did you steal candy from the cupboards again?” she snaps, tone incredulous.
“No, Mom. I wouldn't be telling you if I had.” he bites out. She scoffs.
"Then why do your hands smell like burnt sugar?”
He shrugs, just as confused. His mother rolls her eyes at him, which is code for her thinking, and then stops, as of having realized something. She turns and takes her keys, dragging him to the car despite his protests, eyes growing more panicked by the second.
They drive to the doctors’ office, and his mother demands an appointment. The receptionist leads them to a waiting room and eventually comes back with a doctor in tow. Katsuki is very confused, but his mother is acting more aggressive than usual, which indicates that she's nervous, and he doesn't want to increase her anxiety.
The doctor begins to examine Katsuki, taking a swab of his sweat and handing it over to a nurse. He does his yearly checkup as well, measuring his weight and height.
Two days later, they go back. The doctor says something about results, then tells him he's gotten his quirk.
He explains while his mother latches onto his wrist protectively. When they get home, they tell his father. He nods, a happy smile on his face, and he ruffles his hair, Katsuki trying his best not to flinch. His mom keeps him away from anything hot for the rest of the day, not wanting to spark the nitroglycerin being secreted from his body. The doctor said that although it was a small chance, he still had a chance of developing a sparking method to go with his quirk, taking into account his father's, and Mitsuki spends the rest of the day planning scenarios for that exact outcome.
That night, he wakes to his father holding two fingers to his forehead. He drifts off again when he leaves.
The next day, his palms are sparking. His father is smiling so wide Katsuki is sure his face will crack in two. Mitsuki flinches at the sound of his explosions, but he doesn't notice, too busy admiring his quirk. The teachers fawn over him when he gets to school and multiple students sit with him during lunch. He inches away from them all and ignores the teachers’ praises.
Izuku babbles how cool his quirk is constantly. It's starting to creep him out, but he knows Izuku means well. He's caught on that he doesn't like to be touched, too, so he's doing it less often, which is a blessing in on itself.
For the next week, students from all over, some even in his class are sitting down with him to admire his quirk. They don't let him breathe, and he starts eating lunch outside. His dad is starting to look at him strangely, with a sort of misplaced glee and he doesn't like it.
Then one day, his father sits him down next to him on the couch and pats his head, Mitsuki nowhere in sight. His eyes aren't wrinkled right, and his smile is more of an upward curl instead, brown hair deflated slightly. The sight puts him on edge.
“Your teacher said something interesting the other day,” he starts, and oh no, he's being...blunt. There's no sugar in his words.
There's something wrong.
“Katsuki, do you want to be a hero?”
His father is observing him closely, smile completely gone from his face. The grip he has on his shoulder is tight, clamping him and pinning him to the couch, obstructing any escape routes, and Katsuki doesn't know how to answer. Should he say yes? Or would it be safer to say no? Why does he want to know in the first place?
“I don't know.”
Father leans back, face now eerily blank. He stares at him as if looking into his very soul, and his eyes are empty. He looks dead. Not human.
Katsuki doesn't know if he made the right decision until Father smiles. It's tight, high strung, but it's a smile, and while he hates the fakeness of it, it's the first time he's been comforted by one. The man ruffles his hair and nods.
“Okay.” He says. He hugs him, warm and tight. Katsuki hates it, but just this once, he hugs back anyway. He doesn't want to provoke him any more than he already has.
He let's go, and Katsuki doesn't move as his father stands and walks to his room, slowly and wearily.
He's still sitting there when his mother walks in an hour later, holding the groceries from her weekly shopping. Katsuki doesn't look at her as she walks over, but she cups his face with her hands and pushes his gaze up. There's a strange, vulnerable expression on her face, and he can do nothing but mirror it, exhaustion seeping into his bones as he feels his heart start to calm. Her grip on his face is strong, but not harsh, and it makes him feel safe.
(Years later, he'll forget that moment, pushing away from her soft hands, but for now, he stands and hugs her legs as she sighs and puts her groceries down.)
“You okay, kid?”
Kid. Not brat. He latches on to the softness of it, silently wishing she would call him that more often. A nod is all she gives her.
She scoops him up then, holds him close to her chest as if shielding him, and he clings to her shirt as she carries him to his room and tucks him in. It's warm and tight, and strong, and he reaches for her, this strong pillar holding him up, this boat keeping him afloat. She combs her hand through his hair, kisses him on the forehead, and then holds his hand in hers, a tune humming through the air.
He smiles; his mother sings well. Drifting off, he wonders why she doesn't do it more often.
(He knows why.)
When he wakes up the next day, she's in the kitchen. His father smiles at him, fake. Mom walks out with their breakfast and smiles at him too. Hers is genuine.
He smiles back.