The Heart as Clear as a Mirror and as Still as Water simply meant maintaining a calm state of mind for a time, unshaken by anything from the outside world.
This poor monk had no worldly desires.
Though it felt like cheating to use the system, Yuu wasn't rigid. He always used whatever resources he had. As long as he could achieve his goal, he didn't care too much about the means. Naturally, he wouldn't insist on controlling himself solely with mental strength.
(It's like adding a new line of defense for myself.)
However, the system also warned: Heart as Clear as a Mirror and as Still as Water should only be used in critical moments. While it had no side effects when activated, maintaining it too long could easily affect his mentality.
The worst consequence might be completely letting go of all desires, realizing the futility of the world, and becoming indifferent to everyone except his little sister, whose influence over his hobbies couldn't be shaken.
Yuu's siscon nature was like the Heroic Spirits' Throne of Heroes. It was why he'd survived this long, so it couldn't be easily swayed by something like Heart as Clear as a Mirror and as Still as Water. But other things related to love might not be so certain.
Just as his feelings could be taken by the system, Yuu knew the system's warning wasn't baseless.
(After all, I'll only use it when I really can't control myself… I'm not someone who's easily shaken.)
He smiled confidently. After understanding how to use this tranquilizer, Yuu turned off the light and prepared to sleep with Masuzu.
Don't misunderstand—this was proper sleeping.
The ancient city was peaceful and quiet. The beautiful mountains and waters had melted into the darkness of the night.
The curtains were tightly drawn. The night breeze couldn't enter. The heater hummed, and the room felt like spring.
The lights went out, plunging the room into darkness.
Amid the rustling, the scent of shampoo came to his side, quickly warming the cold bed.
Soft, delicate fingertips tugged at his sleeve. Her breath made his heart race.
"Not doing anything?"
"Not doing anything."
Masuzu moved closer. Her soft, unrestrained body pressed against him. Her voice was slightly teasing.
"Just sleeping?"
"Only the eyes are sleeping."
"Pfft! Hahahaha~" The intimate atmosphere shattered instantly. Masuzu burst into laughter. Her stifled giggles sounded like a clucking hen.
This dirty joke seemed to hit her taste. Her soft, warm body trembled briefly before leaning back against his chest.
"Don't expect me to make the first move. It's my first time, I'm shy."
"It's my first time too, but I'm not planning to make a move." Yuu lifted the arm she was using as a pillow. He turned and hugged her, now using Masuzu as a cuddle pillow.
As he pulled her full, tempting body to his chest, he almost flipped over and rubbed against her. Fortunately, his common sense slammed the brakes at the last moment, stopping all movements that could generate heat. Only his heavy, hot breath flowed against her ear.
Masuzu tensed nervously too. But there was no resistance. She slowly softened in his warmth.
"Hah… hah…"
Their breaths intertwined under the blanket. The scent of body wash was almost entirely overtaken by each other's aroma.
At that moment, to distract himself, Yuu began pondering a question—
What was the true definition of a mature man?
Money? Status? Or just how he interacted with others?
Perhaps all of it. But one sign that a teenager had grown into a mature man was surely starting to think with the lower half of his body.
When someone began facing their desires and admitting they were attracted to another. When they could honestly say, I crave her body—Yuu believed that was when someone could be called mature.
These words might sound crude. Supporters of platonic love would surely dislike hearing them, but that was the truth for the most part.
Many teenagers, when starting their first relationship, often told the girl, "I only like your personality. I have no ulterior motives toward you."
But was that really true?
Don't hide it! If you can't even get excited for her, how dare you say you love her?
For the sake of reproduction, nature dictated that love was always accompanied by sex. Young people just didn't want to admit it. They kept giving while admiring themselves.
Whether they could act on it or not, the desire was definitely there. There might be a few exceptions, but they couldn't deny the general logic.
So, a mature man had a very clear goal—I'm good to you because I want to be with you. I want your body and to be close to you.
How it developed later could be discussed later. This thought was the starting point of love, the primary motivation for seeking a partner, woven from various hormones in the body.
There was no shame in admitting and facing one's desires. It was just incredibly hard to honestly say, "Yes, I'm thinking with my lower body!"
Admitting it in your heart and bearing the consequences of that action was even harder.
In short, maturity in this sense was easily overlooked.
This applied to men and women alike.
Of course, as a mature man, Yuu's desire to have Masuzu was currently at its peak. His mind raced, about to engage the hardware of his lower body.
"…Masuzu, I love you."
His hoarse, beast-like voice sounded. Before desire fully took over, he firmly activated Heart as Clear as a Mirror and as Still as Water.
It was as if a cold towel was thrown over his body. The heat throughout him dissipated rapidly. His racing heart calmed. Even the holy sword Excalibur returned to its sheath swiftly. All desire vanished in that moment.
Closing his eyes, he could even see a tranquil lake appear in his consciousness. The lake's water was blue and mirror-like, as if even tossing a stone wouldn't create ripples.
At the same time, Yuu found his senses sharper than usual.
He could clearly hear the shy, hopeful heartbeat of the girl beside him. He could also hear the voice of someone in the next room talking on the phone while opening a window.
Though his eyes were closed, he could vaguely sense the room's layout. He wasn't afraid of his pinky toe hitting the table's edge without light. Every small movement reflected on the lake's surface.
Yuu quickly understood.
(So that's it—besides being a tranquilizer, it can also make me stronger?)
(My generous and sweet system is incredible. It gave me the power sought by many martial artists, and the cost isn't too bad.)
What surprised him more was that this wasn't an absolute rationality status—his own feelings remained. His feelings for the girl beside him didn't fade at all.
Still, after using it for just a few seconds, Yuu turned it off.
…The efficiency at extinguishing the fire was too strong. He feared if he kept it on too long, even that fire would vanish.
"Go to sleep. We have a match tomorrow."
Saying it lazily, Yuu hugged Masuzu. His breathing was steady, as if holding an ordinary pillow. He closed his eyes peacefully and happily.
"…"
Masuzu, expecting a big battle, felt confused in his warm embrace. She even suddenly felt disappointed and unsatisfied.
"…Did you accidentally enter sage mode?"
Yuu didn't answer. He only gently stroked the back of her head. His fingers lingered in her hair, feeling warm and soft.
Then, she gradually grew sleepy. Masuzu let out a small yawn. She didn't care how her boyfriend suddenly became calm. Like a lazy cat, she closed her eyes too. She rubbed her face against his chest and breath, slowly falling into an unknown dream.
But she had a premonition.
Tonight would be the most peaceful and happy dream she'd had since parting with her mother at seven years old.