I Became the Male Lead’s Adopted Daughter

“You always do that at the last second, Daddy!”
Grumbling non-stop, Leonia was set down onto the floor by Ferio, who then turned and strode toward the center of the training ground.
Leonia scurried after him, still firing off complaints.

“So what, you think being rich, handsome, muscular, and having a high title makes you all that?”
“Yeah.”
Ferio was shamelessly confident.

“Well… that’s fair!”
Leonia agreed with a nod.
“What’s your point, then?”

Ferio poked her lightly on the nose, finding her logic increasingly ridiculous.
Leonia glared at him with a pout and covered her nose with her hand.
“I just meant… you’re kind of annoying, but since you’re my daddy, I’ll let it slide.”

“Thanks for forgiving me for your incredibly shallow reasons.”
“If you’re thankful, write in your will that all the Voreoti estate’s wealth goes to your one and only daughter, Leonia. Include a line about passing down your authority, too.”
“Sounds like you’re plotting to assassinate your father.”

“With that face, you’re the one who looks like an assassin.”
Clearly not one to back down, the baby beast kept snapping and yapping without pause.
“My daughter sure is full of energy.”

If it had been anyone else, Ferio the beast would’ve kicked them out in annoyance. But this little cub, climbing all over him and barking non-stop? He listened with genuine affection.
Just as Leonia had missed her father’s teasing jokes, Ferio had missed her relentless chatter.
“But… why is no one else here?”
In the midst of all her noise, Leonia finally looked around.

No wonder her voice echoed—it was just the two of them in this massive training ground.
Meleis, who had escorted her here earlier, had vanished at some point.
“Today, it’s all ours.”

“Oh my!”
Leonia placed a hand over her chest in mock fluster.
“My heart fluttered!”

“Where exactly?”
Ferio narrowed one eye, suspicious—he didn’t think he’d said anything that would make his precocious little daughter so excited.
“You rented out the whole building for me!”

“Sweetheart, this building already belongs to us.”
For the daughter of the Duke of Voreoti to get emotional over using the indoor training hall within the Voreoti estate…
Ferio seriously wondered if what his daughter needed wasn’t more childhood innocence, but the mindset of someone who could freely wield the power of her family’s wealth.

“Still, you did it for me…”
“Technically, for the knights.”
Leonia still couldn’t fully control the Black Beast’s Fangs. There were too many unpredictable variables.

Especially after last time, when she’d lost control and wrecked everything nearby.
That’s why Ferio had sent all the knights out to the outdoor training field—just in case.
“If the knights got hurt, would you take responsibility?”

“You’re so annoying…”
Leonia’s beaming smile # Nоvеlight # deflated like a popped balloon.
Anyway, the training had begun.

Ferio grabbed a stick nearby and began roughly scratching at the ground.
“The Black Beast’s Fangs.”
He sketched a strange blob on the sparring ground. Leonia crouched and stared blankly at the shape her father had drawn.

It was no illusion—what popped into her mind was a fluffy cream puff, jostled around in a box until the filling burst out.
“…Daddy.”
Leonia hesitated.

“What is this?”
“The Black Beast’s Fangs.”
“…No, it’s not.”

If life had a choice between birth and death, Ferio’s drawing landed somewhere between disaster and destruction.
“The world really is fair.”
“…Do you want this drawn on your face?”

“So what are the Fangs, again?”
Leonia giggled sheepishly, trying to change the subject.
Ferio gave her a disapproving look but sighed shortly and resumed explaining.

If she weren’t his actual daughter, he would’ve kicked her out already.
‘I really must be past my prime.’
Here he was, completely unable to handle his own daughter playing on top of his head.

“…The Black Beast’s Fangs are a power passed down from before the Voreoti family was even called Voreoti. No one knows its origin. Even the oldest records only mention that people with this power lived in the North.”
“The oldest records?”
“The chronicles of the first emperor.”

“There’s such a thing?”
“Your ignorance rivals that mountain range.”
Not one to let things slide, Ferio tossed a casual jab as he scratched two lines beneath the cream-puff-looking “fangs.”

“Ora and mana.”
Leonia had caught the moment earlier when Ferio had hesitated trying to draw ora.
But for the sake of her father’s towering pride, she decided to pretend she hadn’t noticed.

“The Black Beast’s Fangs can use both of these energies.”
Just like ora, which manifested through the body or weapons, the Fangs could enhance physical strength and armaments.
And like mana, which borrowed the power of natural elements for magic, the Fangs could also draw on nature to wield a power similar to magic.

“Oooh!”
Leonia clapped her hands in delight.
“And I think you’ve experienced both, Leo.”

“Both?”
Leonia tilted her head.
She remembered something like magic—during her rampage with the Fangs.

In those scattered, hazy memories, sharp ice spikes had surged upward, and the air turned cold enough to see her breath.
As if the power had responded to the chill in her emotions.
But strengthening her body? That, she couldn’t remember.

“…Maybe back at the orphanage.”
Ferio cautiously guessed.
“Maybe it activated unconsciously when you were being abused.”

He had read the reports Lupe had compiled—about how Leonia had been especially targeted at the orphanage, often clashing with the adults due to her stubborn nature.
Ferio thought it was a miracle she’d survived all that.
The abuse described in those reports was so disgusting, it was hard to even speak aloud.

That Leonia remained sane was nothing short of remarkable.
“It’s likely the Fang lying dormant inside you protected your body and life.”
Of course, it was only a hypothesis.

But Leonia didn’t mind it.
“…Then it was Voreoti who protected me.”
Even in that roundabout way, it made her happy to be connected to her father.

“Hehe.”
Letting out a silly giggle, Leonia squirmed.
“What’s so funny about that?”

This time, instead of teasing, Ferio reached out and tousled her hair with his large hand.
The soft strands beneath his palm, her warmth, the lively sound of her laughter—it was all so pleasant.
He was proud of her for surviving that hell… and deeply sorry.

And, at the same time, a wave of anger welled up toward the parents who had abandoned this child.
“…Now, I’ll show you a demonstration.”
This translation is the intellectual property of .

Setting aside his emotions for a moment, Ferio took a step back. A red gleam, like drifting mist, scattered across his black eyes.
At the same time, the child’s eyes sparkled like gold dust hidden beneath water.
The two sets of fangs resonated.

‘…This feeling.’
It’s oddly pleasant.
Ferio instinctively pressed his lips together, suppressing the grin threatening to rise.

Just having his daughter look at him with such bright, attentive eyes made his chest swell.
He felt a desire to look even cooler in front of her.
For the first time, the Black Beast’s Fangs, which had never stirred anything in him before, felt like something to be proud of.

‘Fine, then.’
If he was going to do this, he wanted to show off properly for Leonia. That thought alone made his shoulders stiffen with energy.
Surrounded by red fangs’ aura, Ferio snapped the wooden stick he was holding in half with one hand.

Crack. The sound of it breaking was sharp and clean, like a strawberry milk candy shattering on the floor.
“This…”
Ferio infused the fang’s energy into one half of the broken stick, then glanced sidelong.

Leonia was watching with high expectations.
Pretending to fumble, Ferio let the stick drop from his hand.
It landed with a solid thud, buried halfway into the floor of the sparring ground like it had sunk into sand.

“Woooow!”
Leonia dropped to her knees and ran her hand across the floor where the stick was lodged.
Not a single crack. No splinters. Not even a pebble had popped loose.

‘But they said this was supposed to be super tough!’
Meleis and Paavo had told her before that the sparring ground, located in the center of the training hall, was made of the most durable and expensive stone the Empire had—strong enough to withstand even three Swordmasters using aura at full strength.
And yet… Ferio had just stabbed into it with a broken stick.

Like biting into a cream puff.
“Daddy, you’re so cool!”
Leonia kept pointing at the stick stuck in the floor with frantic excitement.

“It’s stuck!”
“Yeah, I know.”
“Wow! That’s amazing!”

She cheered like crazy, unable to stand still, stomping her feet in excitement.
‘Having a parent this exceptional…’
It must be exhausting to be a kid like her, Ferio smugly thought to himself.

“So cleanly!”
“I did that.”
His calm reply was soaked in pride.

Next, he showed the final demonstration.
The stick embedded in the ground suddenly burst into vivid red flames. Leonia, who had been watching up close, let out a squeak and fell flat on her bottom in surprise.
“Whoa!”

But her wide eyes remained fixed on the burning stick.
“Daddy, you’re amazing…!”
Overcome with awe, Leonia waved her hands excitedly. The baby beast, having just witnessed the true power of the Black Beast’s Fangs, was now completely fired up.

“…But… do you think I can do that too?”
She drooped.
“Daddy’s so used to it, but I can’t do anything…”

The first time her fangs emerged, it was through overwhelming rage that led to a loss of control—and it had caused a lot of damage.
To make it worse, her memories from that day were hazy. She couldn’t even recall how she’d triggered the power.
She had been full of confidence at first, but now that she was trying, she felt completely lost.

“Leo.”
Two fingers gently lifted the corners of her drooping mouth.
Ferio’s black eyes, now calm with the Fangs’ power tucked away, locked onto hers.

“Everyone has a beginning.”
The Empire’s strongest Gladiago Knights, his ever-capable secretary Lupe, the flawless butler Kara, and Connie, who always tied her hair so prettily.
“All of them had to start somewhere.”

“And I’ll be the one teaching you.”
The black beast himself would be her teacher—what couldn’t she learn? His confident smile said it all.
That arrogant certainty made Leonia’s smile return, even after his fingers let go of her cheeks.

“So don’t let it get to you.”
“Okay…!”
With a burst of determination, Leonia clenched both fists tightly. That meant she’d snapped out of it.

“So, what do I do first?”
What do I need to start with?
Her black eyes sparkled with anticipation.

* * *
Huff… huff…
The sound of panting echoed through the training hall.

“I—I’m dying…”
“You won’t die from just that.”
Leonia, who had barely run three laps around a training hall the size of a mansion, practically crawled her way back onto the sparring platform.

She collapsed right onto the ground, gasping for air.
“Dad, seriously… huff… do you not think I’m your real daughter…!”
The child’s glare was fierce with betrayal.

“What kind of dad cares for his daughter this much?”
Ferio, who had brought her water, looked genuinely offended.
“To properly control the Black Beast’s Fangs, stamina is essential. The side effects can be intense.”

“Side effects?”
Leonia, now seated with Ferio’s help, chugged the water he handed her before asking.
This was a detail that had never been revealed in the original story.

“There are side effects? I thought the Fangs were just unfairly strong.”
“You of all people shouldn’t say that, after how badly you got hurt using them.”
Ah. Leonia nodded.

“So what are the side effects? Are they bad?”
She remembered the days she’d been bedridden with a high fever. Even now, just recalling it made her arms and legs ache.
“Headaches and chills.”

Rashes and hives. Full-body aches with muscle pain—like a brutal flu.
Ferio listed off all the confirmed side effects of the Black Beast’s Fangs so far.
“…Is this some kind of medicine?”

Suddenly, the Fangs sounded like an over-the-counter cold remedy.
And just like that, Leonia’s first training session was over.