Chapter Text
The seemingly endless shifting of the walls, coupled with the almost nauseating sight of floors flipping to become ceilings had Giyuu annoyed to no end.
Most especially when he was starting to notice the familiar yet unwanted presence that he would recognize everywhere, with his eyes closed and with all his other senses blocked.
Tanjirou was also feeling the looming uneasiness radiating from his senior. Confusion and concern etched in his own face whilst occasionally glancing at the Water Pillar, who seemed nowhere near amused with his eyebrows creased closer than what Tanjirou thought was possible.
Aside from being forcibly plunged into an abyss of horror full of flesh-hungry demons, the Water Pillar was obviously bothered about something that Tanjirou didn't know yet.
However, it wasn't long before the answers to almost all of the queries brewing in Tanjirou’s mind came to fruition, in an unpleasant way nonetheless.
For a split second, Tanjirou caught a whiff of an overwhelming scent resembling Muzan’s than he ever did with any other demon.
In a moment, they were advancing to particularly nowhere, and in another, Giyuu was standing protectively in front of him, the Water Pillar’s blue blade shining stunningly amidst the dull brown and crimson red that reflected their surroundings.
Tanjirou had been in this situation before, recalling when Giyuu also protected him from Shinobu.
Yet, compared to that time and right now at this time, only did Tanjirou notice how unusually tense yet intensely prepared his senior was.
Giyuu’s entire stance mirrors a lion ready to pounce at a poor deer, but it only took a second for Tanjirou to realize they were the helpless deer.
For standing right in front of them, was a high-ranking demon with an immense aura of authority and majesty that made his breath ragged just from being exposed to the demon’s sheer presence.
While Tanjirou had no idea if his slight difficulty in breathing at the moment was a result of facing the second strongest demon or the demon’s yet known blood demon art, he was distracted by the scents emanating from Giyuu.
Anger. Fury.
And is that … Sadness?
A quick look at his senior had confirmed that what he was catching a whiff of is right for some reason.
Giyuu’s hand, while tightly gripping his nichirin blade, was also slightly trembling, as was his entire body, albeit in a state of controlled vexation.
On the other hand, the demon in front of them didn't move a muscle, didn't even touch the hilt of his sword proudly displayed by his hip.
Tanjirou stopped on his tracks.
Is this demon a sword-user?
The younger slayer took note that maybe the demon was thinking he didn't need to use it to end them both, considering “Upper Moon One” was conveniently etched in his middle pair of six eyes.
“You have a lot of nerve showing in front of me.”
Giyuu’s words had Tanjirou halt his own thoughts as he quickly deduced something.
These two knew each other.
“Well, it was you demon slayers who entered our territory uninvited.” The demon quickly replied, his tone monotone yet his scent emanating sarcasm.
A huff, followed by his senior’s statement that had a hint of mockery and sass.
“Uninvited? Your master had graciously offered this entire place to us. I'm sure he ran his plans by you first.” Giyuu paused, “...Unless, of course, ‘running by’ isn't exactly a practice among your ranks.”
Even with his own hand on the hilt of his own sword, Tanjirou was starting to sense some kind of awkwardness and tension in the air as he switched his glance from his senior and onto the demon ever so often.
“I do not need to explain everything once again.” The demon quipped.
“And I don't recall you explaining why you suddenly disappeared for six damn months, and when you came back, it's as if you didn't know me. Block me—” Giyuu paused, his stern glance directed at the younger slayer.
“Tanjirou, cover your ears.”
“Oh… okay.”
The latter hesitantly complied and had both his hands cover his own ears.
Giyuu, even with his irritated expression, first made sure Tanjirou couldn't hear anything before he stared back at Upper Moon One.
Then with a sharp, cold tone coated with venom, said,
“Block me all you want, but you can't ungasp from how tight it is.”
The Hinokami Kagura user then caught a scent of… what's that … this is… kind of different in a way he couldn't tell.
Tanjirou didn't hear what Giyuu said, still, it had some kind of effect on the demon, who suddenly shifted his position to the side.
“You do not understand. What I had to sacrifice, and what I had to do. It was a choice.”
Tanjirou caught the demon seemingly opening his mouth to say something more. Yet Giyuu once again beat him to it.
“A choice, Kokushibou?”
“Yes.”
Tanjirou wasn't an expert in this type of unique situations, but even he knows that … Kokushibou should say something other than an emotionless ‘Yes’. Because that was NOT the scent he was catching from him.
“I see.” Giyuu narrowed his eyes a bit.
“It doesn't matter now. I think it's time to take our relationship to the previous level; as merely acquaintances.”
The demon stood still, not saying anything, not doing anything.
However, Tanjirou was close to becoming dizzy with the myriad of emotions playing in the form of the scent coming out of him. The younger slayer thought that Giyuu must have caught that somehow, but his fury and frustration over something they shared seemingly won.
“Don't you… have something else to say?” Giyuu’s voice was a bit shaky and unstable.
Kokushibou merely stood for a few seconds, and Tanjirou knew what he would say next would be in contrast to what he was truly feeling.
“I used to think that you took my breath away, but then I realized I was just suffocated by you.”
No! No! Tanjirou wanted to voice it out. That wasn't the entirety of what Kokushibou probably wanted to say! If the demon wouldn't continue with his true emotions, Giyuu-san would misunderstand!
And he did.
That was it, Giyuu-san’s face contorted into pure anger, him dashing forward, nichirin blade on hand, aiming to land an attack on Upper Moon One.
Before Tanjirou knew it, a protruding moving wall hit him, the force itself enough to throw him a good few kilometers away from the Water Pillar.
“GIYUU-SAN!!!!!!!” His scream echoed throughout the infinite cascading walls and doors of the castle, blocking the last view of his senior.
Tanjirou felt a strong hand grab him steady, and he caught sight of Muichirou, along with the Wind Pillar as they all landed on an open floor plan.
“Tanjirou! Are you alright?!” Muichirou’s entirety reflected concern, whilst Shinazugawa mirrored irritation.
“I'm okay! But Giyuu-san is fighting Upper Moon One!”
Now that, had even Shinazugawa-san’s attention.
“Where are they?!”
“I don't know..” Tanjirou mournfully replied, still, determination was present in his eyes. “We have to help him! Have you seen the others?”
Muichirou nodded, “I was with Himejima-san and Genya before, but I got separated.”
Tanjirou nodded as well, not missing how the Wind Pillar had the slightest sigh of relief. “Genya is in good hands then.” Almost immediately, urgency resumed in Tanjirou’s voice.
“But we have to help Giyuu-san! He's alone! We have to go find him!”
Having the other two agree, albeit with different reasons, they set out to locate them.