Son Seo-yeon, the daughter born to Han Ju-hee and me.
From the moment she was born, Seo-yeon was saddled with the selfish expectations of countless people.
They all wondered just how incredible the talent of a child born to two S-rank Hunters would be.
Contrary to their expectations, Ju-hee and I simply wished for our daughter to be born healthy.
And yet.
After a ten-month wait, Seo-yeon came into the world with a congenitally weak constitution.
It wasn't a problem with any single part of her body; she was born with every system functioning far below average.
It was so severe that even minor illnesses became a matter of life and death at the hospital.
"Joo-hee and I really went through a lot back then."
A bitter smile formed on my lips as I recalled those days.
If there was anything that could improve her health, we would get it for her, even if it was on the other side of the world.
"But it was always just a temporary fix."
After taking something, she would seem comfortable for a moment, but it wouldn't be long before she relapsed.
It was driving me crazy.
We didn't want anything else; we just desperately wished for her to grow up healthy.
"I truly doted on her."
The time when Seo-yeon was young was also when my reputation in Korea was at its worst.
If my daughter ever said she wanted to go somewhere, I would cancel my entire schedule for the day to take her.
After that happened a few times, a number of negative articles about me were published.
And so, after surviving one crisis after another, Seo-yeon reached the age of seven.
While my daughter was stuck in her room, unable to even get out of bed, I watched other children run around full of energy. That's when I made a decision.
I would do whatever it took to change my daughter's frail constitution.
I couldn't do it alone.
But if both of us parents threw ourselves into the effort, there would be no one to look after our daughter.
So I went out, meeting and talking with anyone who might be able to help with my research.
After five years of this, I succeeded in creating two secret arts.
The Secret Art 'Rapid Growth' and the Secret Art 'Metamorphosis'.
"A frail constitution can never be reversed."
There was no way to reverse a congenital weakness.
So I changed my research approach.
I would grant her a growth potential several times greater than that of others.
A child grows with each passing year.
They get taller, and their once-delicate organs and muscles become stronger as they approach adulthood.
I tampered with that growth potential.
While an ordinary child might grow by a total of 10 in a year, I made it so my daughter would grow by 40 or 50.
The researcher who helped me continue this study was the one who named it the Secret Art 'Rapid Growth'.
"No matter how I think about it, it's such a childish name."
Childish name aside, its effect was undeniable.
As overwhelming growth followed her frail constitution, Seo-yeon became healthier with each passing year.
Not only that, but after regaining her health, she even awakened, which accelerated the process further. She eventually developed the ideal physique that any Hunter would covet.
"I never thought I'd end up using this on myself."
As I said, this is a secret art that enhances growth potential.
It was impossible to use on the fully-grown body of an old man, but this body is different.
While a normal person's growth usually stops around their early twenties, an Awakened Being's growth can continue until their mid-to-late twenties.
That meant there was still plenty of room for growth.
"I don't have enough mana to do it to my whole body…"
The method for boosting growth potential is simple.
You just have to push mana deep into the area you want to enhance.
It sounds incredibly simple, but in reality, it's not that easy.
There are only two places in the body where mana naturally resides without our conscious effort.
The core, located below the navel, and the heart.
You can temporarily infuse mana into other parts, but the moment you lose focus, it snaps back to its original place as if it were never there.
"Deeply…"
That's what makes it difficult.
You have to push the mana into a very deep place.
And it's not enough to simply push it in; you have to bind it so that it becomes one with that part of the body, allowing it to influence growth.
"First, the lungs."
With this pitiful amount of mana, I chose the lungs as the first part to enhance.
Judging by how I get out of breath after just a little movement, this body not only has stamina issues but also poor lung function.
To move more and lose more weight, I needed to get less winded.
I slowly pushed mana into my lungs.
The mana temporarily strengthened them, making it feel much easier to draw a breath.
However, what I wanted wasn't a temporary boost but an aid to growth.
I forcibly shoved the mana surrounding my lungs deep inside them.
I infused mana into every single tissue that made up the organ, weaving it together like a knot to hold it in place.
"Hoo!"
The procedure was finished just as my mana was about to run out.
I couldn't feel much of a difference right now, but this sensitive body could tell.
The mana had properly settled within my lungs.
At the same time, a message appeared before my eyes.
[Your Mana stat has decreased by 5.]
The mana stat I had painstakingly raised to 6 had dropped back down to 1.
To make mana settle in other parts of the body, you have to tear off a piece of the source itself—the swollen core—and use that.
Otherwise, no matter how crudely you weave it, the mana will seep out within a few days.
It took a mana stat of 5 just to correct the growth potential of my lungs.
My daughter had this growth correction applied to her entire body.
If I hadn't lost all that mana back then, my World Hunter Ranking would probably be several steps higher.
Still, I have no regrets.
"Though she grew up to be quite the ungrateful daughter."
She grew into a daughter who doesn't even eat with the father who doted on her so much, thinking she's all that now.
And for that, I'm at peace.
During the time when my daughter was at her most lovely and beautiful.
I believe I did everything I could for her as a father.
She left my side a long time ago.
She'll grow up just fine on her own now.
All I can do is wish from afar that her future is filled with nothing but good things.
My diet began to pick up speed.
After boosting my lungs' growth potential, the time it took for me to get out of breath started increasing day by day.
Along with that, I used the 5 mana stat points I had accumulated to enhance my heart's growth potential.
The circulation of the heart and the respiration of the lungs—isn't that what they call cardiopulmonary endurance?
As a result of enhancing both organs, I reached a point where my morning walks with the ajumma no longer felt like enough of a workout.
"Is this the right place?"
So I searched online.
For the gym with the cheapest membership fee in the area.
Walking with the ajumma in the morning, and the gym in the afternoon.
From now on, I planned to work out twice a day.
Following the directions on my smartphone, I arrived at an old, shabby building.
"No wonder it's so cheap…"
Just looking at the outside, I could tell why the price was so low.
As I went up to the third floor where the gym was located, I could see the empty facility through the transparent glass door.
The exercise equipment looked a bit old.
"Hmm, that should be fine."
For now, that was more than enough.
All I needed was a place to walk, run, and lift something.
I carefully opened the door and stepped inside.
At the counter right in front, my eyes met with a muscular Ajae who looked to be in his forties.
The Ajae looked me up and down before speaking bluntly.
"Here to sign up?"
"Yes."
"What for?"
What a strange guy.
What other reason could there be for coming to a gym besides working out?
"To work out, of course."
"Hmm. Just a word of caution, we don't give refunds just because you get shot down."
"Excuse me? Shot down from what?"
Is there a moment during a workout where you could get "shot down"?
Completely clueless, I asked, but he ignored my question and continued with what he had to say.
"It's 50,000 won for one month, 90,000 for three, and for twelve months… 300,000 won."
Hearing the prices, I felt like I understood the Ajae's strangeness.
"I'll sign up for twelve months."
"Oh."
The Ajae looked slightly surprised.
He's got the look of someone who's just snagged a real sucker.
The moment I held out my card, he snatched it and completed the payment.
"Alright, payment's gone through."
The Ajae handed back my card and extended his hand.
"As you can probably tell, I'm the manager here. If you have any questions while working out, just ask."
"Ah, yes."
Now that the payment was done, the Ajae—no, the manager—had become somewhat friendly.
"Planning to start today?"
"Yes, I am."
As they say, strike while the iron is hot.
I had brought a change of clothes and a separate pair of sneakers to wear at the gym, planning to start today.
"You came well-prepared. The men's locker room is over there, so go get changed."
"Okay."
After our conversation, I went straight to the locker room and changed into the clothes I'd brought.
It was nothing special.
A black short-sleeved shirt and shorts.
And a pair of running shoes I'd hastily bought online.
I was leaving the locker room, lightly stretching my body, when I saw a woman doing a bench press.
"Whoa…"
The weight plates on the bar were no joke.
With that much weight, she had to be an Awakened Being at the very least.
"I wonder when I'll be able to lift that much."
How long would it take for this body to get to that level?
Promising myself I'd get there one day, I headed for the treadmill.
"Let's start with a slow walk."
I began walking slowly at a low speed to warm up.
Through the transparent glass, I could see the street below clearly.
I was watching the people pass by, taking one steady step after another, when…
"It is you."
Suddenly, a face popped up right in front of me.
"Ack!"
My startled body did an involuntary tap dance before I was thrown backward, crashing to the floor.
Thud!
When a body this heavy falls, the sound is something else.
"Oww…"
As I was vigorously rubbing my sore ankle and butt, the face from a moment ago popped up again.
"What are you doing here?"
A familiar voice.
I lifted my head to see the face.
The short blonde hair and sharp features were even more familiar than the voice.
This body's natural enemy, Shin Yu-jeong, was looking down at me with an amused expression.
The moment I saw her, a violent reaction surged through my body.
"…Hic!"
Oh, please no.
I desperately hoped it was just my imagination that the smile on her face deepened as she looked at my terrified expression.