—So my door really can level up.
That was the first thought that surfaced in Yuhran's mind.
Immediately after, a second thought followed close behind:
What are the conditions for leveling up?
He was certain he hadn't done anything particularly special recently—no monster hunting, no energy gathering like in some novels…
Wait—energy?
Yuhran rubbed his chin, falling into thought.
A bold hypothesis suddenly flashed through his mind:
What if the door recharged itself?
"Come to think of it, it's been exactly three months since I obtained this door."
"If three months equals one segment, and the progress bar has six segments total, then doesn't that mean…"
In an instant, all traces of sleepiness vanished from Yuhran's mind.
That was great news.
If his guess was correct, then he didn't actually need to pin all his hopes of learning magic on the Frieren world.
It was only a matter of waiting a year and a half.
However, Yuhran quickly shook his head, forcing himself to calm down.
"Not necessarily. What if the next world doesn't have magic?"
"Better be cautious."
He let out a breath. With so little information available, speculating endlessly here wouldn't lead to any solid conclusions.
Left with no choice, Yuhran temporarily set aside these tangled thoughts.
He looked out the pitch-black window—
Anyway, he'd find out in another year.
With that in mind, he swiftly put away the two-world door and went straight to bed, sparing himself unnecessary worry.
...
The next morning.
Knock knock knock.
A crisp knocking sound slowly pulled Yuhran out of his half-asleep state.
"Who is it…?"
He muttered instinctively, and immediately heard a greeting in Japanese from outside the door:
"Uncle, it's me—Mikami Natsu. Sorry to bother you, I came to return the tutoring fee from the other day."
At the words "tutoring fee," Yuhran instantly woke up a bit more.
That girl really had run fast—vaulting straight from a second-floor window down to the first floor.
She looked soft and delicate, but apparently she was an athlete.
Now wide awake, Yuhran yawned, got up, straightened his clothes, and opened the door to let her in.
Standing there was a black-haired girl with a neat ponytail, carrying a black bag in her hand.
Seeing Yuhran, she raised an eyebrow slightly.
"Uncle, I came to look for you yesterday, but you weren't home. Don't tell me you were out on a date with another girl?"
To be honest, she felt rather disappointed—after all, she'd lost a day's worth of tutoring money.
Yuhran was just about to answer when Mikami Natsu had already started rummaging through her bag.
Before long, she took out an envelope, deliberately slowing her movements as she said:
"This is the refund from that day. I'm really sorry—I didn't expect my foster mother to show up and ruin things."
"Of course, if you don't mind, we can continue right now."
As she spoke, she slowly slipped the money back into the bag, secretly watching Yuhran's reaction.
"?"
Yuhran looked helpless, the corner of his mouth twitching.
This girl really had strong professional ethics—but was it really appropriate to say this so early in the morning?
Considering that over the past month, his Japanese was already more or less up to par—
And to prevent a repeat of last time—
After a brief moment of thought, Yuhran decided to politely decline.
Better to wait until things were absolutely safe.
Right now, he needed to focus on training his body to adapt to the long trek of four to five thousand kilometers ahead.
"Huh? Is that so? I see."
Hearing Yuhran's excuse, the girl didn't look disappointed at all. On the contrary, a spark of excitement flashed in her eyes.
She snapped her feet together, raised her hand in a peace sign in front of her face, and flashed a dazzling smile.
"Then please allow me to formally introduce myself."
"I'm Mikami Natsu, a long-distance running ace from Harugaoka High School. I completed a full marathon when I was thirteen."
"If you want to improve your endurance, you can totally come to me."
"I may not be as good as a professional coach, but I'm cheap—and your place is close to my home, so we can train together."
"So, what do you say, Uncle? Want to join me?"
"Don't call me uncle. I'm not that old."
Yuhran retorted reflexively.
But right after that, he felt that the proposal didn't sound half bad.
Training alone really was boring, and he didn't have enough money to hire a professional coach.
But if it was a student, the cost shouldn't be a problem.
The only concern was what would happen if her school found out—he didn't know much about that yet.
"Oh, that's totally fine!" Mikami Natsu waved her hand.
"Even though the school strictly forbids us from working part-time before adulthood, as long as we don't get caught, it's fine."
She looked at Yuhran seriously and said,
"I'm sure you wouldn't tell anyone about this, right?"
"To outsiders, we just happened to meet—friends who like running… no, pen pals."
"As for internal stuff, worst case, I'll just forge a consent form."
"I need money, you need stamina. It's a fair trade."
"So? What do you think?"
Mikami Natsu blinked, her eyes filled with barely concealed anticipation.
If this deal went through, she wouldn't need to work other part-time jobs before entering university—and it wouldn't cut into her training time.
For her, it was a perfect win-win.
Yuhran fell into a brief silence.
She'd already laid out the solution so clearly that he couldn't really find a reason to refuse.
Indeed—if you don't say anything and I don't say anything, no one would know this was an employment relationship.
Yuhran nodded lightly, accepting Mikami Natsu's proposal.
He then invited her inside, and they began discussing the details of the future training plan.
Since Yuhran couldn't stay in Japan long-term, the payment would be calculated daily.
Five thousand yen per day.
Training items included long-distance running, core training, swimming, cycling, and more.
At first, four hours a day—gradually increasing to seven hours.
If maintained for three to five years, an ordinary person could probably reach the level of an amateur athlete.
But Yuhran had the warrior's cultivation method—this time frame should be greatly shortened.
"I don't need to punch a thirty-meter crater."
"As long as I can kill magical beasts with ease, that's enough."
"If warriors can stand shoulder to shoulder with mages, then they must have something extraordinary about them. I hope I can make it."
Looking at the schedule in front of him, Yuhran subconsciously touched the muscles on his shoulder.
They were firm—but still far from steel.
Across from him, Mikami Natsu noticed his movement.
When she saw the bulging muscles in his arms, she paused slightly.
In her impression, Yuhran was supposed to be a shut-in middle-aged guy—but clearly…
She'd underestimated him.
Mikami Natsu gathered her thoughts, coughed lightly to compose herself, and said:
"Then we'll officially start training tomorrow morning at five a.m. Any objections?"
As she spoke, she slowly stood up, a faint smile curving her lips.
"See you tomorrow, Uncle."