The terrifying temperature and slashes quickly melted and shattered the glacier beneath Takeru, and a large number of fish were also caught in the collateral damage.
The barriers Takeru had set up themselves, after being struck by the sword energy, caused layers of ripples. Although there was no sign of breaking, it was enough to show the strength of Takeru's attack.
By the time Takeru stopped, he had gained an even deeper understanding of Sun Breathing. Although he hadn't reached Advanced, he was close.
Most importantly, he had completely mastered these sword techniques.
Then, Takeru looked at the many special fish below, some larger than a person, and directly stored them in his item bar.
After briefly familiarizing himself with Sun Breathing, Takeru returned to everyone. Seeing that they were still listening to the lesson, Takeru didn't disturb them too much.
He went back into the house and prepared to practice the Breathing Technique.
After all, the Breathing Technique was different from mana meditation. It didn't rely on mana or life energy, but solely on breathing to improve physical fitness. So, it could basically be used simultaneously. This made it very necessary to become more familiar with it.
What Takeru needed to master most now was the higher realm of total concentration breathing: [Total Concentration: Constant], where one can maintain total concentration breathing even while sleeping.
Of course, this wasn't difficult for Takeru. With a little familiarization, he could fully master it within a few days.
Besides that, there was the unique ability of the Breathing Technique: The Demon Slayer Mark. The Demon Slayer Mark is closely related to the Breathing Technique. Different people have different marks.
In the Demon Slayer World, almost all the Hashira eventually unlocked their unique marks, which greatly increased their strength and allowed them to defeat the Upper Moons and face Muzan Kibutsuji.
The power of the Demon Slayer Mark is the power to break through one's own limits. It exchanges increased body temperature and pulse rate for increased speed and strength.
This wasn't difficult for Takeru. Besides that, there was a hidden factor: self-recognition.
What exactly constitutes self-recognition, Takeru wasn't entirely sure. But Takeru had no doubts about himself.
As for whether he could truly unlock the Demon Slayer Mark, Takeru planned to test it sometime.
As for the so-called side effect of not living past 25, that was a joke to Takeru. After all, Takeru's vitality was even stronger than Muzan's, and his level of existence was many levels higher.
Takeru could easily overcome even the side effect of the Eight Gates' Gate of Death, let alone this side effect that even Tsugikuni Yoriichi could overcome.
Just as Takeru wanted to meditate and practice the Breathing Technique, Koyuki ran in. Then, taking advantage of the fact that no one else was occupying Takeru, she directly threw herself into his arms.
"What's wrong?" Seeing Koyuki's action, Takeru was startled. Usually, Koyuki was very well-behaved, gentle, and elegant, though also a bit clingy.
"Nothing. I just wanted to lean on Master." Hearing Takeru's words, Koyuki responded softly.
"Is that so?" Hearing her words, Takeru was startled, then didn't say anything else. He gently stroked her head.
Feeling Takeru's touch, Koyuki unconsciously narrowed her eyes, showing an expression of enjoyment, like a cat being gently stroked.
After stroking Koyuki for a while, Takeru closed his eyes and used the Breathing Technique. Almost instantly, Takeru entered the state.
As for Koyuki in Takeru's arms, feeling Takeru stop moving, she curiously glanced at him. Seeing that Takeru seemed busy, she didn't disturb him too much. She just quietly leaned against Takeru and also entered a meditative state.
On the other side, after spending about an hour, Ram and the others had explained the basics of Nen to everyone. Of course, this included simple demonstrations and guidance.
In short, everyone benefited greatly during this time.
Although there might be some initial discomfort, it would definitely become a great help in the future. Even now, the defense of Nen combined with their own basic defense had increased Naofumi's defense by several levels.
Most importantly, because this world has levels, simply leveling up increases one's attributes, and the amount of Nen also slowly increases accordingly.
So, although they had just activated their Nen, relying on their high levels, they all had a very sufficient amount of Nen, which would further increase in the future.
As for their future achievements in the field of Nen, it would depend on their understanding and development abilities.
Of course, Raphtalia, Rifana, and Filo would be following Takeru. As long as they didn't slack off, their Nen achievements wouldn't be too low, whether they focused on Nen or used it as an auxiliary ability.
After Ram and the others told them to disperse, everyone excitedly went back into the house. Because rooms had been reserved for everyone from the beginning, there was no need to worry about insufficient space.
"Master, Master, Filo has mastered Nen!" Upon returning, Filo excitedly wanted to go find Takeru and share her joy.
"Wait, Filo. Takeru-sama is training. You can't disturb him recklessly." Seeing Filo's action, Ram slightly extended her hand. A gust of wind controlled Filo.
"Eh, I'm sorry, Shishou." Seeing Ram's serious expression, Filo lowered her head and apologized.
Seeing Filo realize the problem, Ram canceled the wind control, allowing her to move again.
"Such exquisite control!" Watching Ram's casual move, Glass and the others were completely stunned.
At first, they thought Ram and Rem were just ordinary maids. But after learning they knew Nen, they thought they were somewhat special.
However, seeing the wind magic Ram casually released just now, Glass and the others completely understood that Ram was far from simple.
After all, being able to casually subdue the lively, active, and quite powerful Filo couldn't be ordinary.
"Shishou?" Hearing Filo's address to Ram, Yui, Mio, Therese, and the others were surprised.
"Yes. Takeru-sama had Nee-sama instruct Filo in wind magic, so she is also Filo's master." Facing their surprise, Rem explained further.
"So that's it." Hearing this, everyone nodded thoughtfully.
After this small episode, everyone quietly entered the villa. Seeing the serious expressions of Ram and Beatrice, they were naturally worried about disturbing Takeru and upsetting them. After all, they were quite aware of the three's terrifying strength.
Soon, Filo walked towards Takeru's room. As she opened the door, she saw Takeru meditating on the sofa, with Koyuki leaning against his embrace.
"Ah, Koyuki is so sneaky, secretly monopolizing Master!" Seeing this, Filo puffed out her cheeks. However, because of Ram's earlier reminder, Filo didn't dare disturb them.
"Is the lesson over?" As everyone returned, Takeru directly opened his eyes. He had sensed them as soon as they entered the house.
"Yes. Did we disturb you, Takeru-sama?" Hearing Takeru's words, Rem asked worriedly.
"No." Hearing her words, Takeru shook his head gently.
"That's good." Hearing Takeru's words, Rem breathed a sigh of relief. She looked very well-behaved and cute.
"Alright, it's getting late. Everyone should rest early." Looking at them, Takeru spoke directly.
"Yes." Hearing this, Ram and Rem had no objections. They directly made the bed and waited for Takeru.
Takeru didn't stand on ceremony. He carefully carried Koyuki up. Then, Filo quickly got next to Takeru, followed by Beatrice, Ram, and Rem. Raphtalia and Rifana didn't leave either. After simply changing into their pajamas, they also lay down.
Although surrounded by beautiful women, in this situation, Takeru naturally couldn't do anything inappropriate. He then closed his eyes and continued familiarizing himself with the Breathing Technique.
By dawn of the next day, Takeru opened his eyes. After a few hours of familiarization, Takeru had completely turned Sun Breathing into his own solid ability.
After that, thanks to the hard work of the many slimes throughout the night, Takeru's level had reached 126.
That meant he had leveled up sixteen times overnight. After quickly allocating his attribute points, Takeru felt his strength increase again, if only slightly.
It was now five o'clock. Although he could still let the slimes hunt, there was no need to push for that little time. Thinking this, Takeru teleported out of the room.
Arriving at the still-hard-at-work slimes, Takeru directly took them back into his portable space. He also separately collected the monster corpses and drops from the Space Slimes' bodies.
Looking at the Space Slimes' bodies filled to the brim with monster corpses, Takeru showed a smile. With these corpses, after returning, he really wouldn't lack materials for creation.
He just wasn't sure how many points it would cost. If it was too many, Takeru would inevitably have to give up some.