Chapter 13: The Demon Swordsman.

The desolate moon shone upon the beautiful flowers of wisteria around the butterfly mansion. The manor was silent as the gentle breeze caressed the trees, bringing the soft rustling of leaves with the songs of the crickets. The ambiance was perfect and a lone figure was experiencing all of it as it lay on the tile roof.

His yellow robes were bathed in the moonlight as his raven hair glistened softly, with his eyes closed he just lay there motionless. His lips were curled up in a smile because of his comfortable position, with the gentle breeze came the faint sounds of the people in the manor.

The triplets helping Aoi make dinner, the patients groaning and resting. Few of the ones in better conditions chatting on different topics, there was one voice that caught his attention the most. A determined voice softly counting the number of slashes she made with her blade.

Kanao was practicing swordplay in her quarters, tirelessly without relent. Everything was perfect but Zenitsu, who was lying on the roof sprang up to his feet and jumped a few meters away from where he was ac moment ago.

The tiles where he was lying on a second before were destroyed and a figure stood there on the end of the roof.

The figure was illuminated under the moon, a demon stood across Zenitsu, the pale-skinned man was tall and muscular, with long and spiky black hair with red tips that he kept in a ponytail. The most notable feature on him was the three sets of eyes on his face with yellow irises and red sclera that have black straight lines diverging from each iris. His middle set of eyes features the kanji of 'Upper Rank One'.

Zenitsu knew that the demon he was facing was nothing like the ones he had fought before, the demon before him was Kokushibo, the strongest demon under Muzan's command.

Kokushibo wore a purple-and-black bee-hive patterned long kimono and black umanori-styled hakama pants tied with a white uwa-obi. He carried a fleshy katana at his waist that had eyes in the space between the tsuka ito wrapping of the handle of his sword.

Kokushibo stood there with his blade unsheathed, the tsuba and blade had eyes and veins adorning it gave a malicious vibe. Zenitsu was caught off-guard, the menacing aura Kokushibo gave off his entire being was frankly stifling. Zenitsu, for the first time used the INVENTORY skill God gave him; he took out the blade given to him by the God himself, a blade that had a legend of its own, the demon blade, ENMA!

Thanking himself for carving the SECTUMSEMPRA runes on it when he did the same for the other Hashiras. Zenitsu took off his haori, matching his gaze with Kokushibo, he drew his blade. There was pin-drop silence, with leaves rustling in the wind were fading out as the wind came to a still.

"Let's change the location, somewhere open, somewhere we can fight without being interrupted. The valley in the north looks like a suitable place, are we agreeable?" Zenitsu spoke in a calm voice.

The menacing aura Kokushibo gave off was pressuring Zenitsu's mental capacity, but with each passing second, his resistance grew stronger as his own aura was tempered. Kokushibo noticed this and gave an approving nod, despite the fact that they were enemies, who were going to fight till death.

This was the temperament of a swordsman, the temperament of the strong. Zenitsu smirked, taking out the bottle of poison he smashed it on the floor. He jumped down from the roof and landed on the ground and flashed away into the forest.

In an open field in the valley, the two swordsmen faced each other, blades drawn, they took stances and charged in.

KAMINARI NO KOKYU~ ICHI NO KATA- HEKI REKI ISSEN. <THUNDER BREATH~ FIRST FORM- THUNDERCLAP AND FLASH>

TUSKI NO KOKYU~ ICHI NO KATA- YAMITSUKI-YOI NO MIA. <MOON BREATH~ FIRST FORM- DARK MOON- EVENING PALACE>

Both the swordsmen flashed in speed normal eyes could not follow, the blades met as the sparks flew. The collision was anything but silent. The clinks and clanks rang as the two exchanged swords before meeting each other in a blade lock, Kokushibo being the one with the superior physique exuded his tyrannical might. He pushed off Zenitsu, sending him sliding over a few meters while his feet did not buckle an inch.

KAMINARI NO KOKYU~ ROKU NO KATA- DENGO REIGO. <THUNDER BREATH~ SIXTH FORM- RUMBLE AND FLASH>

TUSKI NO KOKYU~ SAN NO KATA- ENKITSUKI- TSUGARI. <MOON BREATH~ THIRD FORM- LOATHSOME MOON- CHAINS>

The swordsmen sent chains of far-slashes against each other, thunder rumbled and the wind whistled when they fought and their blades met. The moon like discs met the thundering slashes, cancelling them out; the swordsmen stood in their stances as the wind from the collision ruffled their hair and clothes.

"I have to say, you are well deserving of the title you bear. No other demon I faced could hope to match your calibre, I have a proposal to give if you are interested." Zenitsu spoke.

"Your strength grants you the right, speak your mind, RAIBASHIRA. Maybe you can give me the fight I have been longing for in the past decades of my life. But know this, Muzan-sama has ordered me to bring your head and I shall deliver; struggle with all your being and fight for your life." Kokushibo spoke in a grave voice.

"We might be human or demon, but there are things that we are similar in, our love for the blade and the swordplay, our relentless pursuit for strength, our talent and our will. The will to not bow, to stand up against the odds, the unbending, unyielding will to never give up." Zenitsu spoke in an iron-like voice, sharp and cold, strong as it was merciless.

"I ask for a duel, a match of our skill, a match till one of us is left standing; a match where nothing interferes, no blood techniques, no breathing techniques, no status, nor titles. I desire a battle like that, would you grant me that?" Zenitsu spoke as the blade he held hummed in excitement.

"Very well, but remember; if you make a farce out of your spoken words, your end will be anything but good." Kokushibo answered with the same conviction.

"Fine, and even if you know this already, I will remind you that before my blade nothing is immortal, nothing is invulnerable. You shall be as mortal as any other man when my blade meets your flesh, do you still dare to cross swords with me knowing very well that it could cost your life or limb, do you dare to put that on stake as you swing your blade?" Zenitsu challenged.

There were no words, the blades did the talking. Zenitsu triggered the power of Avalon to reinforce his body and bolster its strength. With that boost, Zenitsu met Kokushibo on equal footing, despite that, Zenitsu was pressured.

The countless battles forged the sword style that Kokushibo had, the passing years tempered it to what it was today. With talent and a body to adapt, the only thing Zenitsu lacked was experience, and for that sole reason, he decided to have a battle on pure swordsmanship against Kokushibo.