"You're Kage Rigakure, right? I'm Ru... A Dark King troop, we are undefeated, yet one of your men defeated Fu... It's been the last hundreds of years since one of us was defeated by a human. The first human to ever defeat one is you, remember? You defeated me, you let me escape and that counted as being a traitor and betraying your comrades," the unknown Dark said, who was fighting Kage Rigakure and was named Ru.
Their blades collided, causing them to fly away from each other. Kage Rigakure comes to a halt and stays firm as he hears the mysterious figure speak, revealing a recognizable face behind the mask that causes his eyes to widen. 
"Who are you?! Hundreds of years? What are you talking about?! A human can't live long like that! Hahaha!" Kage Rigakure said as he suddenly laughs. He laughs out loud that Fukeshin Gakure and Kiroshuku Hakure heard it.
"You know I'm right... You were a friend of mine back in the day," Ru remarked, widening his eyes before closing them and opening them again. It was now fierce and searing, and he was suddenly calm.
"What the hell are you talking about? A Friend?... Don't you talk like you're my friend, you bastard! You're not my friend, you stole his body, meaning, you also have his mind... Then he must've locked it. He's still inside you, isn't he? I'm just a Hashira, you little ant, you're Ru, right? Let me tell you that you're a piece of trash... You and your Dark King good days are over, it's time to end it," Kage Rigakure said in a calm voice as he dashed forward and reached Ru.
"You know, he once said that peace wasn't an option," Ru continued as he abruptly caressed his blade menacingly. He notices Kage Rigakure stab him in the chest, but it goes through him and he feels no pain. He slowly fades in front of him, and he realizes he's simply an afterimage. He looks to his left and sees Ru standing sideways in a wall, staring at him. 
"You shut up... You know nothing about what happened! You weren't even born when that happened, secrets are secrets, they can be hidden forever or revealed one day," Kage Rigakure remarked calmly.
"Oh, I know everything... Of how you took a powerful energy from darkness and turned you immortal. I'm not sure about that, but your age is 123, right? Meaning you've been in more than just three eras, old man... You won't get away this time, I'll murder you just like I murdered your friend," Ru said as he abruptly vanished, standing sideways on the wall.
"And you thought I didn't know you in the first place? There was a man who betrayed humanity and chose to be an immortal, and I heard he's part of the Dark God horde, I hope he's not dead yet because I'm the one who'll kill him... He's the only reason we failed the mission. I will torture him until I die, then bury him alive with his hands and feet tied... Who cares, collaborating with a Dark God who solely seeks destruction is enough punishment... What do you think about the folks that sought to safeguard all they care about?" Kage Rigakure asked menacingly, slowly turning around to see Ru appear behind him."
He was ready to strike his blade down towards Kage Rigakure's neck when he notices him utterly unfazed He was furious as he didn't even defend himself but instead displayed his menacing aura. Ru came to a halt in his position as Valkyrie and Cavalry stood behind him. 
"Kataku Sukure, we thought he was like you and the other Hashira's that were with him, it was just like it like you asked, you have no chance of winning Kage Rigakure, you're in a weak Era and this is the time we conquer this world... Hidden or not hidden, this Era is weak like you in the past where you were born, that Era is weak because there were kids and the Untold Stories... We failed because we didn't realize there were gods, legends, myths, and beings we couldn't explain! Now that they're gone, there's no one to stop us! Certainly not you! No other swordsman or swordswoman will be able to stop us because we are sick of waiting and will now unleash our whole force to this earth to destroy everything you humans love! Ahh!" Ru yelled angrily as he flew at Kage Rigakure. 
Kage Rigakure flew backwards when he saw his furious and great fearful aura, and he raised his right hand with his sword and put it in front of him to intercept the approaching strike from his blade. He didn't realize Valkyrie and Cavalry had come behind him without being aware of it.
They were pointing their swords behind his back when a dark gateway appeared from behind him, causing him to whirl around to his left and see Cavalry next to him and a Bright Dark gateway. His eyes widened when he realized he was hovering and couldn't move.
"Tsk! I'm locked in! Hmm! I guess they got me!" Kage Rigakure thought as he was sent inside the dark bright portal with Ru. It abruptly closed as soon as Kage Rigakure and Ru flew in.
In the concealed underground tunnel. Kage Rigakure remained sharpening his blade, sensing that his clone had entered a dimension. He sighs and puts his right hand beneath his chin and his elbow on top of his hips as he stops sharpening his blade.
"They teleported my clone into a new dimension, Hahaha! I guess they haven't realized.... Sheesh Ru is in big trouble if the Dark King finds out. Fukeshin Gakure and Kiroshuku Hakure can take care of Cavalry and Valkyrie, but that would take too long because they are unkillable. Oh well! I guess they gotta find a way to kill them," Kage Rigakure said outloud as he giggled and went back sharpening his blade.
Kiroshuku Hakure and Fukeshin Gakure noticed Kage Rigakure had been transported to another dimension. They were both standing menacingly as they both looked up and saw Cavalry and Valkyrie smiling and standing menacingly as well.
"Whatcha look at that! The two of you remained! You're Fukeshin Gakure right? It's impressive that you manage to teleport those Hashira's and Shira's in such a short amount of time without using all of your energy! I guess this Era isn't so weak after all!" Valkyrie said menacingly as he dropped his sword and pulled out an axe behind him. When he was ready to grab for his axe, it glitched and a Dark axe materialized behind him. 
Cavalry on the other side also drops his sword on the ground and raises his right hand to reach something behind his back. Suddenly, he drew out a mechanical Dark weaponized rifle. It was seven feet long and appeared to be a shotgun combined with a sniper. It was as bright as Valkyrie's axe. 
"This thing is called a Cavalry gun. It's used with a sniper and a shotgun. This existed in the past, but now it's not because we killed every single one of the men who made these kinds of stuff. This thing sold for a lot back in the day, this Cavalry gun was surely hard to make and... Rare to find, this gun made our job worse and a lot harder. I believe the country has made this new fantastic weapon!" Cavalry said in a happy voice as he held the Cavalry gun with both of his hands and it appeared that it was bigger than him. He pointed it at Kiroshuku Hakure in the far distance.
He pressed the trigger with his right hand, and a huge boom noise was heard as something came out from inside the rifle and caused the noise. There was smoke everywhere from where it landed, and it was aimed at Kiroshuku. 
"Ash! They're ashes for sure! My gun didn't miss! And they're both weak! Sorry Valkyrie! I took care of them for ya!" Cavalry said as he turned back and started walking. He stopped walking when he heard a cracking noise behind him in the distance. The 700-foot-tall tree was down in a single blow. It was gradually falling down, and smoke was still enveloping the area. The big tree was going to fall to the ground, destroying some farms and a river in the distance. 
It makes contact with the ground, causing the entire underground land to quake. The vapors dissipate, and two swordsmen kneel in the grass, with a broken tree and a large hole left by Cavalry's gun behind them. 
That made Cavalry turn around and see Kiroshuku Hakure and Fukeshin Gakure kneeling on the grass and catching their breaths. His eyes widened when he saw them and he smiled even more as he saw that their Kimonos and coats were ripped apart. He also sees something strange about the two that makes him stop smiling. 
"Those two have pushed their limits even further, Cavalry. Stay here, I'll take care of them both this time, shoot them when you see a blindspot. I thought you didn't miss Brother," Valkyrie remarked with a smirk. He suddenly flew towards Kiroshuku Hakure and Fukeshin Gakure. They were both giving off no movement and crouching menacingly with their swords in their right hands. The smoke was still covering their vision, and they could only see their shadows.
"It appears that the unexpected has begun... Problem after problem... The other Hashira's and Kataku Sukure were in bad condition. I'm sure the Hashira's that were with him are still lying on the ground, I can't believe this, south!" Kage Rigakure said as he sighed. He raised his head and looked at the ceiling. 
"Cavalry gun," Fukeshin Gakure and Kiroshuku Hakure said together. They spoke it calmly, but their eyes were sparkling from a distance. Valkyrie came to a halt a distance away from them after noticing their eyes flashing brightly and matching their mask. 
"What in the world?! Who the hell are these swordsmans?! Two glowing masks! How is that even possible?! In this Era, how could they still exist!" Valkyrie exclaimed angrily as he saw someone in the distance swing his sword in the air at him and launch an air strike.
That made his eyes widen and he flew up. He looked down as he flew up and saw a wind attack sent by Kiroshuku Hakure. It was a piercing attack that could split him in half. 
"How can they move?! They're exhausted. How can they do such things?!" Cavalry said furiously as he raised his Cavalry gun and pointed at Kiroshuku Hakure who stood menacingly with his right eye widened and glowing bright. There was bright white smoke around his right eye. 
"This new eye makes me feel warm and cozy... I feel like I'm not exhausted at all, but I'm sure I'm so exhausted... I'll probably collapse but at least we will manage," Kiroshuku Hakure said as he raised his head and glanced at Cavalry, who had his gun pointed and ready to fire. Suddenly, he sees him pulling the trigger and an energy light starts in the middle of the gun. It fired and it burst out and it was different and aiming for Kiroshuku Hakure. 
"Wind Dragon! Fearless slash and dash," Kiroshuku Hakure said in a calm voice, as all of a sudden wind was covering his blade and he swung it as soon as the Cavalry gun fired. Valkyrie was about to land on the ground as he slowly turned his eyes to his left and saw the Cavalry gun fired and the wind dragon about to reach each other. 
He had his eyes widened and at the last second before they collided he smiled. It collided and it made a powerful force and a powerful shockwave that shocked the whole underground land. Valkyrie evaporated as everything in there was just pure smoke and an energy ball with a dragon around it floating in the air and making destruction on the ground. It was sinking and Kiroshuku Hakure and Fukeshin Gakure were flown back away. 
Cavalry got thrown back away and let go of his Cavalry gun at the same time with his eyes widened. He was hovering as he sees the shockwave that break his neck and body. Fukeshin Gakure and Kiroshuku Hakure was nowhere to be seen in the smoke.
They got sent away and slammed into the river and they were next to the giant seven hundred-foot tall tree. They quickly rise to the surface but it's still sending air and shockwaves and a powerful force that is also sending the water out of the river.
"Fukeshin! Let's get out of here. Can you teleport?! If this continues, this whole land may break apart!" Kiroshuku Hakure said to Fukeshin Gakure, who was on his far left. 
"I'm sorry! But I can't! I'm weak and the hidden technique is fading! We need to keep an eye on Valkyrie and Cavalry! They might be here! This hidden underground land could be used for something else... Destroying this whole place is such a waste. No wonder Kage Rigakure is protecting it," Fukeshin Gakure replied as they both swam down the river and swam towards underneath the giant massive tree that was taken down.
On the other hand, Kage Rigakure had finished sharpening his blade as all of a sudden he heard footsteps approaching that made him stand and grab his blade with his right hand and let go of the tool that he was holding in his left hand. 
He glanced to his right and saw a light in the far distance. It was a purple-white light lantern and a woman approaching. That made him put on his coat and hoody as he smiled behind the mask. Suddenly, he started giggling as he heard her stop walking.
"My, my, what do you think you're doing here, old man?" The woman asked as Kage slowly turned to his right and saw her a distance away from him. She was holding a lantern and Kage could see her aura. She was wearing a mask and a coat and a kimono on the inside. She was also a swordswoman. 
"Just passing by... You, what the heck are you doing on this route? I thought you were going the other way around, that's why I passed here," Kage Rigakure answered as he heard her giggling. 
"I hate you so much! Till this day! You know... Also you've been not focusing on the outcomes I thought you were a great captain back in the day, Kage Rigakure," she said as she began to walk and approaches him. 
"You still hate me? Come on! I thought it was okay! But not... You're the Shadow Guard Hashira of this place, right? Well, you've been here in the Dark place holding that lantern of yours... It's a gift from your master, isn't it? I still remember the gold old days. It was like near a diamond but it quickly shattered into pieces the gold that we were protecting and the fire that was in our heart, our village! We failed to protect it. Now we stand here as guards, that Legend that stopped the world from getting conquered pushed back the Dark God near its death. I was so mad and furious when I heard that he had died because of old age!! He should have accepted my offer! If he accepted my offer that should've been the end of his evil schemes!" Kage Rigakure said in a furious voice as he sat down on the ground and the swordswoman was on his left side also sat. She was wearing a dress kimono and a coat. 
She was strangely calm as all of a sudden they heard a loud boom noise not that far away. The underground tunnel was shaking as they both sensed a powerful force that made them both silent for a minute. 
"You should've known at the start that he would never accept something that came from the dark. You should remember that there's one more enemy besides the Darks and the Legend's Behind the Masks are further investigating into them... They are more terrifying and terrible than the Darks. These dark have killed millions, countless peoples in the world... But we have nothing to do with it but protect this hidden land. There are more of us in the other parts of this world, but we can only connect it with these kinds of tunnels and I'm the only one who can do it. We are at the same age and on the same page, Kage Rigakure, and also this is the first time that you miscalculated. Kiroshuku Hakure and Fukeshin Gakure are in big trouble and your clone is on the other dimension. You should remember that the Legend left us to make this a better world. At least a hundred of us are still left out there in the open and we are somehown't aged and still alive and almost still a teenage version. We should provide backups if they need to without exposing our guarded places. They may think this era is weak, but it's not. It's full of new legends that will also be born. The other Masters have fled with their students and I believe that Shikari Gakure is one of these legends and Gakushin Gakure. They're the ones we need to give attention to, especially because Kuro has trained Gakushin Gakure, the Dark God doesn't know, but she has escaped his wrath," she said as that made his eyes widened as soon as he heard Kuro. 
"As expected from Kuro... She still has her skills even in this current era, and I can't believe you've already made a formula... Impressive as always, you made stops in the underground tunnels, didn't you? I can't believe that this was actually made, far beneath the land and far beneath the Sunken City," Kage Rigakure said as they both stood up menacingly giving no vibes. They were both calm as Kage put back his sword in his sheath in his left waist.