**SPOILER alert: Attention! This entire chapter is a past event, and part of it is similar to chapters 235-236 in the manga about what happened to Shigaraki's family. I added my own twist to it, but the major event that happened in the manga still happens here. Read at your own discretion.

Disclaimer: Boku no Hero Academia characters and plot events belongs to Horikoshi Kohei.

To Be a Hero

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Shiragiku was looking around the big house with curiosity. Being two-and-a-half, everything held a sense of wonder and she loved to get her hands on anything. But right now, she had a mission in mind. She was going to find something to cheer up her brother so he won't cry anymore. Her stubby legs walked clumsily around the hallway that led to a wooden door. It was the door she recognized as her father's office, and it was slightly ajar. The man must've left in a hast this morning after scolding Tenko and forgot to close it. This was going to be the first time Shiragiku will get to see what the inside looked like!

Pushing open the heavy door, she was so excited that she fell over with a soft thud. Not deterred however, she got back up and let her eyes trail around the large room. Everything was bigger than her, from the big wooden desk to the black swivel chair. There were a few things strewn on the ground, mainly books and crumbled pieces of paper and she looked at each of them curiously. Unfortunately, she found that none of it would be sufficient to cheer up the crying boy.

Her brother liked heroes, and there was nothing resembling of that around here!

With a small, childish huff, she crawled out from under the large desk. But as she tried to stand by gripping onto the swivel chair, the wheels on the chair slid back and she went along with it.

Crash!

As Shiragiku fell to the ground, the chair hit the shelf on the wall and caused a small book that was carelessly placed on the edge of the shelf to fall onto the ground next to the girl. Shiragiku sniffed back a tear as the photo that was sticking out of the fallen book caught her attention.

The photo itself was old, but the people on it was still visible. There was a strong-looking lady in there that had a very nice smile and black hair. She was holding a small boy lovingly and the boy was grinning back at her; they looked alike. But what struck the girl the most was what the lady was wearing.

A hero suit!

The lady in the picture was obviously a hero!

If she showed this to Tenko, then the boy will be happy again, right? It wasn't a hero figurine but with her childish reasoning, a picture of a hero was basically the same thing as a hero figurine.

"Ara Shiragiku-chan, what are you doing in there?" The grandmother was surprised when she saw Shimura Kotarou's office door wide open and had come in to look and saw a surprise. The little girl peered up with a toothy smile and the old lady's heart melted. Shiragiku was really too much like her late daughter. "What do you have in your hands?"

"Hero!" the girl replied with a happy smile, waving the photo around.

The grandmother looked at the picture and let out a small noise. That's Kotarou when he was younger…

She remembered that her late daughter told her about her husband's situation and the reason why he was so against heroes. Anyone would hold a little resentment if their parent had decided to give them away in order to focus on being a Pro Hero, she supposed. It was the reason why she never says anything when Kotarou lashes out on Tenko for being so fascinated with heroes; she can only pick up the pieces and console the poor boy after.

"Are you interested in heroes, too?" she wondered with a small frown. It would be bad if Kotarou started to lash out on the girl as well, after she could articulate more words and start to show her interest more obviously.

"For nii-san!"

Her response made the old lady pet her on the head warmly. "Ah, Shiragiku-chan really loves her brother, doesn't she?" she asked, and the little girl nodded. With a small chuckle, the woman kneeled and got the girl to sit on her lap as she told her a little about the photo since the girl was so excited.

"This is your father, see? He must be around Tenko-kun's age in here. That lady is your other grandmother on your father's side, and yes, she is a hero. Due to certain circumstances though, she had to leave the family. That's the reason why your father doesn't like Tenko-kun talking about heroes," she explained slowly and watched Shiragiku for any semblance of understanding. The little girl was staring intently at the photo and she sighed. "Shiragiku-chan, this is a secret between us, okay? Don't speak of this to your father… You know how he doesn't like to talk about heroes, and he won't be happy if you went around spouting that your other grandmother was one. Do you understand?"

However, hearing that only confirmed Shiragiku's excitement. All her little brain could register was father and grandmother and most importantly, hero. This was all she needed to cheer up Tenko, she knew of it! "I no tell daddy," she promised but snatched the photo out of the old lady's hand. "But I go show nii-san!"

"S-Shiragiku-chan? You really shouldn't take this photo—"

But it was too late. The little girl was already clambering down the hall with the photo in hand to show her brother of her find. The old lady sighed and got up. Perhaps it will be fine if Shiragiku only showed it to Tenko for a little while… Then she will return it back into Kotarou's office before the man comes back.

[]

"Nii-san! Nii-san!"

Tenko had ceased his crying, but he was hanging out in the yard by himself still. Next to his crouched form was a pile of dust and he had his face in his arms. He was tired.

"I told you to go away, Shiragiku…" his grumble was muffled by his crossed arms. But Shiragiku was relentless and kept tapping the boy on the shoulder.

"Nii-san, I found hero!"

That made Tenko raise his head. The underside of his eyes was rubbed raw and there was dry tear-streaks on his face, but his eyes were blinking in surprise when he saw the photo in the little girl's hands. It was a picture of a young boy and a hero. "W-What is this…?"

"Hero grandma," Shiragiku pointed at the beautiful smiling lady with a proud look. Then her finger shifted to the boy, "Daddy!"

Tired ruby eyes widened. That boy in picture was his father…? He couldn't deny it because there were some resemblances to himself. While Shiragiku was a copy of his mother, Tenko inherited some traits from his father and the lady in the picture had the same mole as Tenko on her lower chin. It was undeniable, but it was almost unbelievable… His father who hated heroes… Was the son of a hero?

"Our grandmother was a hero…!" he clutched the photo with shaky hands and looked at Shiragiku. "Where did you…?"

The girl giggled when she saw that her brother was so surprised. That means she did well, right? "Grandma say itsa secret," she put a tiny finger up by her mouth. "Shhhh secret! Other grandma is a hero."

"But why are you showing me this?" Tenko wondered. His mind was a mush; he couldn't believe what he was seeing… Or what he was currently feeling. He felt a small hand hold onto his rough and dry fingers and his eyes trailed down to the smiling face of his little sister.

"Because nii-san wants to be a hero."

Even though she was very young and her brain can't comprehend complex things yet, she was able to understand that the boy admired heroes. Perhaps it was because he thought that heroes can save everyone; or maybe he just thought they were cool. Either way, he was surprised that she could see it. He hadn't felt that kind of warmth from anyone except his mother when she was still alive.

Tenko's lips quivered slightly and a smile of his own finally appeared on his face. His little sister snuggled closer to him.

Maybe one day… We can be a brother and sister duo…

[]

"Tenko-kun, Shiragiku-chan! Come back inside, I have snacks."

The two children didn't move from their spot by the garden; more like Tenko couldn't move because Shiragiku had fallen asleep leaning against his arm. It had been a long day for the both of them.

"Tenko-kun?" Grandmother called out to the two kids who were out in the yard. She then saw that the little one was asleep and carefully picked her up. "Ah, I'll put Shiragiku-chan to bed. You come in too, okay?"

The dark-haired boy nodded and stood up; the photo flitted down to the ground and he picked it back up and smiled at it. Things were starting to look up for him now. Even though his father hated heroes, he now knew there was a connection for him and heroes. He'll keep it a secret for now so that he wouldn't get in trouble… But still, he was happy. There was a hero in his family!

Carefully, he tucked the photo in his shorts pocket and ran inside the house. Maybe tomorrow he and Shiragiku can go to the park with their grandparents and they can play hero-saves-the-civilian…

When his father came home early a few hours later, Tenko was sitting in the living room with his grandmother and grandfather. The news station was on and there was a special report about a violent attack in another city, but the country's Symbol of Peace, All Might, was there to defeat the villain with his mind-blowing strength and ever-present smile.

He wondered if he'll ever get to meet a hero like All Might one day.

"So cool…"

"What did I say about watching that crap?!" Kotarou scowled as soon as he walked into the room and saw that his son was marveling at a hero on the screen. He immediately shut off the television and glared at the boy. "Haven't you learned your lesson?"

"Kotarou-san…" Grandmother started, but she didn't do anything.

The man only continued to glare down at the scared boy. "Any talk of heroes is forbidden, that's the rule in our family. Stop your silly little daydreams," he said while giving Tenko a look of disgust before turning around.

Why…

Something within Tenko's body snapped. He couldn't keep quiet about it after all, not when he knew he had a grandmother who was a hero. His father looked happy in that photo too, so would he set such an unreasonable rule upon this family?

"W-Why?!" he called out with a shaky breath, making the man stop on his tracks and the two grandparents gasp slightly at his bold defiance. The boy's body shook as he stood, and the old photo fell out of his shorts.

"Where…" Kotarou's eyes saw red. "Where did you get that?!"

Tenko could feel fear travel down every inch of his skin but he was angry, too. He was angry and tired. Why couldn't his father see that?!

"T-Tenko-kun, apologize to your father now," Grandmother said as heavy feeling weighed on her; she completely forgot to take away the photo after getting Shiragiku to bed. If the boy told the man where he got the photo from, little Shiragiku may not be safe from his wrath, either! "Let's not make a big fuss..."

Why isn't grandmother on my side? Tenko's ruby eyes narrowed. Now that he thought about it, his grandmother and grandfather was never on his side when his father was letting out his anger on him. They only stood and watched and came afterwards to console him. But what he needed… What he needed was someone to stand up for him!

"I asked you where you got that, Tenko!"

"My o-other grandmother w-was a hero, wasn't she?!" Tenko blurted out. "So why can't I like heroes?!"

SLAP!

The terrible sound resonated across the entire house before everything fell silent. Tenko could feel a stinging pain on his cheek; his head snapped to the side with his eyes brimming with tears and disbelief.

"That person was not your grandmother," Kotarou's eyes was hard without regret. He went to grab the photo but Tenko threw his body on top of it to save it. Enraged, the man raised his hand again, "It was that demon who threw away her own child…"

He's going to hit me again—

"Listen up. A hero is nothing but someone who hurts their own family for the sake of helping others."

Someone, do something…

"Please…" Tenko whimpered with tears flowing down his eyes. "I d-don't understand…! Grandmother—"

SLAP!

"Never speak of her or other heroes again, you hear me?!"

It hurts.

It hurts.

It HURTS.

There was a terrible itching feeling within Tenko and his hands reached out to the man who was walking out with the crumbled photo. It wasn't just his cheeks that hurt, his felt his entire body was on fire. Something was happening to him and he was itching to get rid of it.

"Tenko-kun…"

Grandmother and Grandfather looked apologetic as they came over to the crying boy. Their hands laid on his small, shaking shoulders and caused him to turn to look at them with eyes filled with wild mistrust.

They stood and watched. They've always just stood and watched.

"Let's go upstairs and I'll read you a story, okay?" the old man tried to console with a guilty expression. "Don't cry anymore."

Why is it that they only ever tell me to stop crying…?

"We are still a happy family, right?"

I can't take it anymore.

"Tenko-kun?"

"I…" his wet ruby eyes glazed over with anger as his hands grabbed onto both of his grandparents' arms. "I hate you!"

The old couple barely mustered a scream as their bodies fell apart into pieces. Bile immediately rose up into Tenko's throat as he looked at what happened in horror; they simply disintegrated into a pile of blood and ash. All he meant to do was to throw his grandparents' hands off him…

Was there a villain attack?

...Or did he do this?

"N-No…"

He couldn't breathe. It was like something was grabbing his throat and he couldn't let any air in. His head was pounding, and his skin was burning with that itch that won't go away.

"I didn't mean to… I didn't…"

He tried to grab onto the table to steady himself only for the wood to crack and crumble under his palms. The tears ran down his face even more as realization hit him. It was him. He did this. He killed—

A foot stepped into the living room and a gasp was heard. Kotarou's face was etched with horror as he looked at the distraught and crying boy hovering over a pile of blood and ash. "What—?!"

"F…Fa-Father…!" Tenko scratched at his itchy skin in agony as he stumbled forward. He was destroying everything he touched. "I-I'm s-so sorry…!"

Scared, his father grabbed the broom that was nearby and swung at the boy who was trying to reach him with those murderous hands. "Stop it, Tenko! You… You monster!"

Monster…?

Tenko felt his heart clench painfully as he cried out. The itch was intensifying, and his father was right. He needed to stop it. With full intent to kill, he charged at his father and touched him in the face as the man came crashing down.

"Die! Die! Die…!"

"T-Ten…Ko."

That was the last word his father ever said before he crumbled into a pile of blood and ash, just like his grandparents. The boy heaved and cried, but interestingly, he found that he was no longer itching as it had been satisfied. Somehow, it felt good…

But he looked at his two hands and his body started to shake again. The Quirk that he had managed to manifest, the Quirk that wasn't so strong until he was filled with blind rage—it had destroyed his entire family.

"...Nii-san…?"

A small voice called out and Tenko whipped his head towards the staircase where Shiragiku was descending with sleep still in her ruby eyes. She was going to see what he had done; the person who was as warm as his mother was going to see this and run away from him, too.

"Nii-san is sad? Why?" she whispered before her eyes landed on the destruction behind him. She clutched at her shirt for a moment with terror. "B-Blood…"

Tenko's chest started to clench again and he found himself reaching for the girl, "I-I…" To his surprise, Shiragiku didn't run away. Instead, she ran towards him and with her small arms she wrapped it around the boy tightly.

"S-Scary!" she cried into his shirt for comfort. She didn't know what had happened; but even if she did, she loved her big brother and she was going to hold onto him for dear life. Her warmth made Tenko calm and he stopped his heavy breathing. His hands fell back down to his sides and he cried with the girl in the middle of the empty hall, not looking back at what's left of the destroyed and blood-stained living room.

"Nii-san, n-no more family?" Shiragiku hiccuped.

Their whole family was gone and they only have each other to depend on. What can they do? They were nothing but orphans now.

"Shiragiku, let's run away… A hero will come save us…"

Note: this is not told directly from Shiro's perspective. She still hasn't remembered this part yet. Also, this is far from the end of the sibling's origin... More to come later. Please leave a review! :)

Side note: my obsession with Tanjirou's Dance of the Fire God theme song in epi 19 of Demon Slayer is unreal...