Mount Natagumo.
The thick darkness of night enveloped the entire mountain forest, and endless ink filled the dense woods. Even the starlight in the sky could not shine at all.
It was like a deadly silence sleeping in the mountains, and it seemed that no living creature could survive here.
Shun stepped lightly on the mountain grass while holding the heads of several Demons he had just decapitated in one hand.
Except for the kind "mother" from the original work whom he had driven away, the other Demon heads were writhing and roaring in his hand.
The sounds of pleading and curses echoed in the distance.
Shun did not listen to this, humming a song with great interest.
Finally, when he reached the midpoint of the mountain, the long-awaited Twelve Kizuki at the end of the month—Rui appeared.
He was a short boy with white hair, wearing a snow-white kimono with a spider web pattern, and the words "Lower Rank Five" were etched in his left eye.
"Shut up!"
A disgusted growl was heard. It was unclear whether it referred to the Demon crying out in sorrow or to Shun, who was singing cheerfully.
In an instant, the howling Demon fell silent as if it were being choked.
Shun looked at them with great interest.
"You are the leader here and the brother of this 'house game'? Your whole family is here."
As Shun said this, he threw all the Demon heads in his hand into the sky.
Suddenly, Rui narrowed his eyes, and several threads of spider silk detached from his hand, trying to reclaim them.
Unfortunately, Shun's sword was a step faster. The solar energy from the Sun Breathing attached to his blade transformed into a red slash like a burst of fireworks in the night sky, turning the Demon heads into flying ash.
"Oh, your father is dead! Your sister is dead!... Well, it seems your mother is also dead."
Shun's words changed Rui's expression.
Rui had a twisted obsession with family bonds. He believed that no matter what happened, parents should protect their children, and older brothers and sisters should protect their younger siblings, even at the cost of their lives.
Yet now, the 'home' he had painstakingly built was turned to ash by an unforgiving opponent.
Unable to contain his anger any longer, Rui revealed his eyes with the words "Lower Rank Five" etched in them, staring at Shun as if he were choosing someone to eat.
What greeted him was a pair of Mangekyo Sharingan with six-pointed stars!
Shun coldly uttered a single word:
"Tsukuyomi."
Tsukuyomi is an illusion cast by the Mangekyo Sharingan of Uchiha Itachi in his left eye. This technique can pull the enemy's spirit into an illusionary space, controlling all factors including time, location, quality, etc., by the user. Once controlled, the enemy will suffer tremendous physical and mental pain in the illusionary world, and the pain experienced by the opponent is exactly the same as the pain in the real world; as long as the opponent looks into the eyes, they will be attacked.
Moreover, Tsukuyomi is the strongest mental attack in the Naruto world. Typically, Tsukuyomi cannot be broken. Only those whose Sharingan is stronger than the caster and possess strong mental power can break it.
In the world of Kimetsu no Yaiba, Tsukuyomi is unbeatable.
As he unleashed the illusion, he easily sensed Muzan's spiritual power present in Rui's body.
It was precisely because of this that Muzan could control the Twelve Kizuki and understand the enemy's intelligence through his eyes.
Shun did not want to reveal his abilities, easily shielding this spiritual power, and then he entered the Tsukuyomi illusion space.
Upon seeing Shun's appearance, Rui, who harbored a grudge of "killing his father, killing his mother, and killing his sister." could no longer think of the strangeness of this space.
"Blood Demon Art: Cutting Thread Cage!"
What came toward him was a slash as red as fire.
"Sun Breathing First Form: Dance"
The red blade slashed in an almost perfect circular arc, cutting through the Blood Demon Art, and at the same time, attacking toward Rui.
Rui continuously executed ferocious killing moves. Shun, who had just learned Sun Breathing, was enjoying fighting his opponent.
Gradually, Rui realized that the opponent's swordsmanship was becoming increasingly skillful.
In the end, Shun merely stood there, and twelve forms of Sun Breathing transformed into flawless solar discs, turning all his vampiric attacks into ash.
At that moment, Rui even hesitated; despite the heavy rain pouring down on the young man, he might not be able to surpass the opponent's solar discs.
Finally, there was a brief pause in his attacks using Blood Demon Art, and a fire dragon emerged to kill him!
"It's over…"
At the moment of death, the feeling of "finally being freed" arose in Rui's dying heart.
And the next second!
He, who was supposed to die, unexpectedly came back to life in this space.
'Why..... is this happening? Wasn't I supposed to die after being decapitated?'
At the end of the strings, Rui was too exhausted to think about it, as Shun had already run toward him with his sword in hand.
After the battle, hope emerged in his heart. Although he didn't know why, he felt that the opponent's physical condition seemed to be deteriorating?
The young man's physique had previously been like a monster, and even Rui could not compare to him.
However, this time, the opponent's physical fitness was only at the Hashira level!
"This time, I will definitely kill you!" Rui now full of fighting spirit, uttered harsh words!
❀❀❀
Three hours later
Rui, who had risen, found that the opponent's physical fitness had declined again!
"I can't kill you at the Hashira level, but I will definitely kill you when you are weak now!"
❀❀❀
Eight hours later
"You are only slightly stronger than an ordinary person now!"
"I will definitely kill you!!!"
❀❀❀
Twenty-four hours later
"Ahhhh!!!"
"Why?"
"Why can an ordinary person die with me?!"
❀❀❀
Three days later
Shun in the Tsukuyomi space looked helpless. He used his sword to poke Rui, who was lying on the ground like a corpse, not forgetting to encourage him.
"Come on!"
"A little more, just a little more, and you can kill me."
"Can't you get up and try harder?"
"How can you sleep at your age?"