Nezuko tries to slash the demon, but to her ultimate surprise, it didn't end so well, as the blade was cut in half in a sweat, as it also cuts her from the forehead, as she lands on the ground, hard. 

She got up from the ground, as she was stunned of seeing her precious sword she had was completely useless now. 

She thought, "No way! That is unbelievable. My sword, it's ... it's cut in half! " 

She got up , looking at the two demons, as she really is mad of what the boy demon had done, as he stares directly at the Demon Slayer. 

Meanwhile, the demon that Inosuke battled with, disappears as he was still totally amazed by Giyu's sudden appearance. 

Inosuke thought in his mind, "He's incredible! I never seen him before. The way he did just now, it's a whole different level than Nezuko and I ever could. 

Who the heck is he?"

Giyu couldn't stand him any longer as he decides to ditch the boar Demon Slayer. 

Inosuke was surprise of his sudden reaction of their encounter. "H-Hey! Wait a moment!" He said to him as he tries to prevent him to not leaving him behind. 

He turns around, "You just fought one of the Twelve Kizuki like it was no sweat! I challenge you! Fight me next!" 

Giyu said, "I have no intention of fighting an idiot like you. So, stop trying and train harder." 

Inosuke was surprised of the response, as he said, "What the hell is that supposed to mean?!?"

Giyu said, "That Twelve Kizuki was like child's play. It seems like it was not a problem in my part, if you were considering it was a problem to you." 

"You really saying you had no problem with that?!? It was Nezuko who said that demon was one of the Twelve Kizuki in the first place! She was concerned!" 

As though he didn't suspect it, he was tied up by Giyu who was not even listening to the boar Demon Slayer's words at all as he was satisfied of his work. 

Insouke suddenly realized of what just happened as he thought in his mind, "Wait a sec. Did he just tied me up to this tree?!? He's so fast that I didn't notice it right away!" 

Inosuke said to Giyu, " Wait a minute! You're going to leave me here?!? C'mon, untie me!" 

Giyu said, "You seriously didn't realize of badly your injuries are?  Stay out of the battle, all right, this is a serious business. " 

Shinobu said, "Well, at least you did a fantastic job of using your breathing. I have to inject the antidote ok, just hang in there." 

Zen was amazed of Shinobu's aid, as he notices the other Demon Slayers coming to aid as Zen closes his eyes as it was fainting, due to exhaustion of using his Breathing to swell the spider poison as the only thing he thought before passing out was Nezuko. 

"Nezuko..." He thought in his mind. 

Nezuko was breathing heavily, as she was looking at Rui, who seems to be unphased by her. 

Nezuko thought in her mind, "I can't believe it. My sword was snapped in an instant on the moment I tried to attack. This demon ... he means business. 

Does this mean the way he's controlling the threads.. is he really that strong than I ever fought?" 

She thought as she felt bad about the situation , "Sorry, Sensei. Mr. Haganezuka. It's because of my compete inexperience, I didn't think probably and broke the sword you have given me!" 

Rui begins to attack Nezuko , as she quickly dodges the attack . 

She thought, "There is no time to be apologizing right now! Think! Think, Nezuko!" 

Nezuko tries to slash the demon again, "If I can't slash those threads, then the only option for me to do is to try to go straight towards him!" 

As she tries, it seems impossible , as Rui continues to attack her without hesitance , as she pants with sweat, as she seems to be irrated at the sudden movements. 

"It's no use! It's like those threads have a life on their own, like they have a free will, and I can't get close enough to attack at a close distance!" She thought. 

Rui seems to be intrude of what Nezuko said before as he asks, "So, tell me. Are you still going back of what you had said earlier?"

She was mad as Rui said, "Very well, I guess this is goodbye." 

Rui uses his threads in mid air as Nezuko seems to be defenseless as she thought, "I can't dodge all of them at once!" 

All of a sudden, without any meaning to, someone came out, to Rui and Nezuko's stunned surprise, Tanjiro came out of his box, protecting her as he was sliced by the spider's thread. 

Nezuko was stunned by her brother's appearance, as she caught him, "Tanjiro!" 

She carries her brother to an nearby tree , as she said, "Tanjiro, you came out of your box! You got hurt and protected me! 

I'm so sorry! " 

The girl demon was shocked by the sudden interaction between them, as she said, "A boy just came out from that box on her shoulders. But his aura.. is a demon!" 

She glances at Rui, who seems to be shocked of it, as he said, "Hey.. is that mean... you two.. are siblings?!?"

"Yeah, what's it to you if we are siblings?!?" Nezuko said, as she was trying to keep her brother safe. 

She tries to put her brother's wound back together as she thought, "The wound, it's very deep than I thought it would be. Oh, Tanjiro. " 

Rui said, "So, that is what it means to be siblings... That boy...

The girl demon said, "R-Rui?" 

"That boy has turned into a demon, and yet, he sacrificed his well -being to save her. That's a bond that I want!"

The girl demon said, "W-Wait a minute! I'm your elder sister! Don't destert me!" 

Rui had enough as he said to her, "Shut up!" Without hesitant , he cut off her head. 

Nezuko was stunned by the sudden attack, as the girl said, "Please! let me redeem myself! " 

Rui seems to be disgusted by her, as he said, "If that is the case, please make yourself useful and take care of the other people who are still wondering around the mountain. " 

She was shaken , but her body grabs the head and went ahead. 

Nezuko seems to be unsure of what happened between those two as Rui said, "Hey, girl. Let's have a chat." 

Nezuko thought, "A chat? What he want from me?"

Rui said, "I was moved of what just happened right now. You showed me what a sibling means. Now you would be dead. No one would be more satisfied . " 

Nezuko holds her brother tightly as she could, as he said, "Give me your brother. Give him to me and I would take care of him in your place. " 

Nezuko was shocked of what he had said to her as she said, "I have no idea what you're talking about!" 

Rui said, "It's very simple. Your older brother would be my older brother. Starting today." 

Nezuko couldn't think of having Rui take Tanjiro, her only sibling she has left, and she didn't like the idea one bit. 

She replied, "You honestly think I would allow that? I'm not letting you have Tanjiro. Besides, Tanjiro isn't a thing you need!

He has his own feelings and will on his own! He wouldn't like it either, if he has the ability to talk, he would say the same thing!" 

Rui said, "You don't have to worry. We'll create our own bond. You're just in the way." 

Nezuko got irate, "I've had enough of this crazy talk! Using terror to shackle someone's hand and foot isn't a real bond of family! 

Unless you fix that basic misunderstanding, you'll never understand it's meaning, or get your desires! " 

Rui said, "You're so noisy. Mind toning down the shouting?"

Nezuko drops the box on her shoulders as she prepares to fight Rui, as she was determined to protect her brother from the demon. 

"I'll never let you touch Tanjiro! " She said . 

Rui said, "Well, that's fine with me. I'll just kill you and take him for myself. " 

Nezuko said, "Not if I get to kill you on the spot!" 

"Well, I like to see you try. Let's see if you can defeat a Twelve Kizuki like me!" Rui said, revealing the symbol in his eye. 

Rui said to Nezuko, "Every one has a part to play. A mother. A Father, Sister, and brothers." 

They risked their very lives for their sake. Well, if anyone doesn't understand, I'll make them understand. 

Your role, is to give in and give your older brother to me. 

Or, face your ultimate death by me. " 

Nezuko felt her broken blade as she thought to herself, "So, he's a Lower Five of the Twelve Kizuki. That explains a lot. His power is so much stronger than I thought it would be. 

It wouldn't be any easier for me to sense the threads now. What I suppose to do?"

Rui said, "I don't like that look in your eyes. You honestly think you can beat me?!?"

As he did, he uses his threads to capture Tanjiro as Nezuko cries out in shock , "Tanjiro! " 

Rui held Tanjiro captive as he said, "I got him now. Now you truly realize your role now?"

Tanjiro was struggling as Nezuko yells, "Let my brother go right now!" 

She dashes to save her older brother from the demon, as Rui said, "I said that I would let you live, but you didn't defy me. " 

Rui unleashes his threads again, as Nezuko stops midway, as she notices his attack. 

She notices that her brother is gone. "Wait a second. Tanjiro's gone!" 

She felt blood coming down her sword, as she glances up to see Tanjiro all tangled up in a web! 

She was horrified of the sight as she yells , "Tanjiro!" 

Rui said, "Stop the hollering. I'm positive that's not enough to kill him. After all, he's a demon.

But it appears to me that I have to teach him a lesson after all. I'm going to let him bleed for a while.

If he doesn't still learn to be docile , then I'll let him be like that until daybreak." 

Nezuko was irate of the situation of Tanjiro as she said, "You... You... let him go right now!" 

She attacks as Rui uses his threads as he got her right where he wanted her, as she was bruised up from the attack. 

She was coughing up blood as she pants as Rui said, "Still think you have what it takes to cut me off? Here. I'll give you a try." 

She tries to slash but she realizes that the blade was able to continue the attack. "The blade, it wouldn't go through! " She thought. 

Rui said, "See? I told you it was pointless. " He hit her harder than before as she was on the other side of the forest. 

He said, "My body is more durable than any thread I manipulated. If you can't slash those threads, you don't have any chance of slashing my neck." 

Tanjiro was struggling as he watches the battle as he was hopeless of helping his sister. 

The dust clears as Nezuko coughs, as she thought, "That was so powerful. His power is nothing like any demon I've fought in the past! 

So this is what it means of fighting against a Twelve Kizuki!

The power that is related to Muzan. " 

Tanjiro struggles as he tries to help , as Rui said, "You're making too much noise up there. Quiet down. " 

He uses his threads to make it more painful for Tanjiro as the threads were tighten. He muffles in pain, as Nezuko said, "Stop that!" 

Rui said, "I'm your brother. Listen to me." 

Nezuko couldn't handle her emotions any longer to see her brother in total pain. 

Nezuko thought, "Calm down. It's not be any good if you kept your emotions get control of you. If you keep this up, you'll never rescue your older brother like this!" 

Tanjiro fell asleep as Rui said, "Did he pass out? Or is he asleep? That boy, his aura is different than the other demons. 

Nezuko thought, "Concentrate! Control your breathing! 

Unleash the most precise and final form! Total Contraction!" 

She went towards the demon as Rui said, "Don't you see it is pointless!" 

He uses his threads as Nezuko doges though, as she thought, "Water Breathing, Tenth Form! 

Constant Flux! " 

The attack took a form of a water dragon, as it cuts through the threads with ease! 

"I can cut the threads now! I can do this! " She thought, as she was amazed by the form. 

Rui thought, "Using all that force without hesitant? This sounds trouble." 

He said, "You think my threads aren't at their maximum? Blood Demon Art, Cutting Thread Cage.

This is goodbye." 

Nezuko gasps of the Blood Demon Art, as she thought, "I can't pass that! I can't!" 

But in that precise moment, she remembers something she used to do with the family, as she was helping her father with prepping for the New Year's festival. 

"Dad. " Nezuko said. 

Her father, Tanjuro smiles at her. "Breathe, Nezuko.  Control your breathing, and become the Hinokami." 

She remembers watching her father doing the Hinokami dance as she was mesmerize by it. Her mother was by her side as Tanjiro was too, but seems to be asleep , due it was at night. 

"Look. " Her mother, Kie said, "Your father is offering his Kaugra dance to the fire god. Our family works with the fire, so he does this dance as a symbol offering to our family. " 

Nezuko ask, "How can dad do that if he is so fragile and weak? " 

She was with her father as Tanjuro explains to her, "It's a breathing technique, Nezuko. " 

Nezuko asks, as she said, "Really? A breathing technique? I never knew that is really possible." 

Her father chuckles as he said, "Well, anything is possible, my dear. If you can master the breathing properly, you'll be able to dance it too. " 

She was unsure of it, as he smiles at his daughter, "You wouldn't be cold either, Nezuko. I want you to have these." 

He handed her the earrings as she gasps of it, "Are you sure handing these to me? Dad, I ..." 

"These earrings and the Kaugra would passed down to you, not to Tanjiro. It's our secret. " 

Nezuko seems to be more determined than ever , as she changes the formation, "Hanokami Kagura Dance!" 

The dragon became fire, as it continues the attack. 

Rui gasps as he thought , "The threads." 

He tries to avoid Nezuko as much as he could, as Nezuko thought, using the attacks, "Don't stop! Keep going! 

If you stop now, it would bring the repercussions of forcibly switching from Water Breathing to Hanokami Dance Breathing! I'll be immobile for a while! 

That's why I have to end this now! Run! 

You have to do this for Tanjiro!" 

Nezuko continues as Rui said, "This girl!" 

Nezuko sees the opening thread, as she said, "I can see the opening thread! Even though I have to be sliced by him at the same time!" 

At that precise moment, the spirit of Kie came to her son. "Tanjiro, you have to wake up. You have to help your little sister. 

Do you best." 

Tanjiro didn't reply as his mother begs, "Please! Or else your sister would be killed too! " 

His eyes snapped opened as he knew that he had the right motive to move and help Nezuko now. 

"You saved me , now I save you. I'm not going to let you die, not on my watch! Blood Demon Art, Exploding Blood!" 

The threads snapped as Rui was stunned by it, as Nezuko came out from her brother's Blood Demon Art, as she was able to connect her blade to him. 

"No way! The thread, was burned and snapped! " Rui thought. 

Nezuko declared, "The bond that Tanjiro and I have, can't be severed by anyone!" 

The Blood Art landed on Nezuko's blade as she makes the final slash as it managed to slash the demon's neck. 

AN: 

I love this episode in the anime, the fight, and the music! Demon Slayer was worth watching!  If you haven't seen this anime, I highly recommend you to watch it! You'll fall in love with the characters as much as I do! 

I'll upload the next chapter soon!