It was only after Mizuki perfectly demonstrated all the current Sword Forms of Snow Breathing that Yoriichi truly realized how difficult Snow Breathing was to cultivate.
He honestly had to wonder if the Demon Slayer Corps would question their life choices when reviewing the Cultivation Manual Mizuki left behind, given how haphazardly the Breathing Techniques were mixed together.
Compared to the physical requirements of Sun Breathing, Snow Breathing virtually encompassed all existing Breathing Techniques.
This inevitably leads to one result: practitioners of this Breathing Technique cannot perfectly master all the Forms.
If they cannot adapt to Thunder Breathing, they cannot master the Seventh Form; if they cannot adapt to Sun Breathing, they cannot master the Ninth Form.
Not to mention that Snow Breathing itself originated from the Wind Water Breathing Technique. With these conditions layered one upon the other, it is practically impossible for anyone to master it... In the following days, the siblings practiced sword skills in the mountains outside the city whenever they had time.
Under Yoriichi's guidance, Mizuki's progress was astonishingly fast.
Even Yoriichi began to marvel at Mizuki's talent.
He thought to himself, "This level of talent might already surpass my Elder Brother."
This applied to her talent in both the Breathing Technique and as a swordsman.
It must be noted that Mizuki had never systematically studied swordsmanship before the age of eighteen.
Previously, when he was in the Demon Slayer Corps, Yoriichi was often out on missions and also had others to teach, so he hadn't spent much effort on Mizuki.
Now, he had ample time to instruct Mizuki.
Furthermore, becoming a Demon also solved Mizuki's only weakness.
Namely, the weakness of being female.
In terms of combat strength, females are naturally inferior to males.
But now, Mizuki can even easily wield a scarlet blade using the power of her Demonization.
Although, looking at the scarlet blade in her hand, she herself felt more fear.
Undeniably, she had become stronger.
The battles between the two in the mountains began to be noticed by passersby.
During that time, rumors even circulated within the city that the God of Fire and the God of Moon were fighting in the mountains outside the city.
This was because some people saw a silver full moon fall from the sky, and others saw scorching flames flash.
Naturally, no one believed it at first, but some people delved deeper. When the curious visited the mountains outside the city to investigate and discovered the dense, non-human battle scars in the woods, they were scared sick.
The large mountain outside the city gradually became regarded as a forbidden zone, and people dared not enter or exit easily.
As the stories became more and more outrageous, Mizuki and Yoriichi also restrained themselves significantly.
In fact, from Mizuki's current observation, the intensity of this world, compared to novels in her previous life, was at most a High Martial World.
Even someone as strong as Yoriichi could theoretically be stabbed to death by a child holding a knife if he didn't move.
His physical fitness was not even comparable to her current physique, which rivaled steel.
Whether in terms of physical fitness or the power of her Sword Forms, she was clearly stronger now.
Yet, Yoriichi could always use his ultimate speed to counter and defeat her.
The speed at which Yoriichi executed the Twelve Forms of Sun Breathing instantaneously was something Mizuki still couldn't clearly see, so it was no wonder Muzan questioned reality.
It seemed to confirm the saying: In martial arts, speed conquers all... After finishing their sword training, the siblings lay in the quiet dense forest. The insects and wild beasts around them had long since disappeared.
As summer arrived, Mizuki said, "Elder Brother, I want to visit Tankichi's house soon."
"Mm." Yoriichi was startled for a moment, then softly agreed.
"You should come too, Elder Brother."
"..."
Mizuki sat up and looked at him with a half-smile: "Could it be that you're embarrassed to go back because your departure last time was too solemn?"
Giving away earrings and performing Sword Forms.
Yoriichi: "..."
Seeing Yoriichi remain silent, Mizuki raised her eyes and pondered, "If you don't go, what if I lose control then..."
"...I'll go."
Mizuki smiled slightly. She asked him, how do you like this open conspiracy!
Although Yoriichi trusted Mizuki, Demons are unreasonable, inhuman creatures.
He wouldn't be surprised if Mizuki truly lost control of her desires one day; it wouldn't be Mizuki's fault.
Humans certainly possess willpower that surpasses limits, but some things cannot be overcome by willpower alone... When they saw Mr. Yoriichi and Miss Mizuki again, Tankichi's family was extremely happy.
Moreover, it seemed as if Mr. Yoriichi's emotional burden had been lifted, and he smiled more often.
Tankichi was happy about this for a long time.
During their last visit to Tankichi's house, Mizuki had guessed that the blue spider lily bloomed in the summer.
This time, she indeed found it.
On a night in August, Mizuki stared at Shi's grave for an entire night but didn't see any flowers.
During the day, she had Yoriichi go and stake out the area.
Although he didn't understand Mizuki's intentions, he dutifully stayed until two in the afternoon, discovering the flower suddenly blooming during the hottest part of the day.
"Ah~"
When Yoriichi plucked the spider lily and brought it to Mizuki, he was curious what she intended to do with it, only to see Mizuki open her blood-filled mouth and swallow the blue flower raw.
Tankichi's family: "..."
Yoriichi: "..."
Licking her lips, Mizuki commented, "It doesn't taste good."
!!!
Of course! It wasn't even cooked!
Everyone's pupils dilated in shock.
Yoriichi frowned slightly: "What exactly was that?"
Mizuki said seriously: "Muzan seems to have been searching for this. Perhaps it's something that allows Demons to overcome the sun."
Yoriichi's eyes narrowed slightly, "Overcome... the sun?"
Mizuki sat inside the house and stretched her finger toward the light in front of everyone.
Sizzle... Mizuki retracted her finger without changing her expression, and the flesh rapidly regenerated.
Mizuki mused: "I shouldn't be wrong. Perhaps a certain quantity is required."
Sumiko looked in surprise at Mizuki's finger, which had recovered in the blink of an eye, and hesitated before saying, "I think I sometimes see that flower behind the house."
"Yes, it's behind the house. This flower should only bloom in the summer."
"I think so. We even ate it as wild vegetables before," Sumiko recalled.
Tankichi's expression changed, and he said seriously: "If it truly allows the Demon King to overcome the sun, can we use it as bait to lure him out?"
Mizuki and Yoriichi simultaneously shook their heads.
Mizuki said helplessly: "That guy is very cautious, especially while Yoriichi might still be alive. He absolutely won't show up personally."
"Instead, it might be counterproductive."
Sumiko suddenly stood up, hoisting a hoe she had nearby.
Everyone looked at her in confusion.
"If we just destroy that flower, we won't have to worry about the Demon finding it, right?"
"That way, he can never overcome the sun."
You're too clever.
Mizuki complained internally for a moment, then quickly stopped her: "Wait, Sumiko."
If you do that, Muzan might truly become unbeatable.
Nezuko is the protagonist's sister! The only Demon besides Tamayo to break free from Muzan's control.
Maybe she'll team up with Tanjirou for a brother-sister mixed doubles fight against Muzan in the finale.