The Tenth Pillar. (Kimetsu No Yaiba X OC)

Heroes always arrive late.

He disengaged himself from the girl while trying to parry the attack, much to his surprise the impact sent him flying through the wall, such brute force.

Hiiro's golden eyes were full of fire as he took a quick look at the girl, she was injured but now she was safe.

The girl looked at him, she was still processing the image of the boy in front of him, he was like a mirage. Yet, he was real, a little curve formed on his face.

"Yo." He knew that the girl used all of her remaining strength to stand up, the pain should be unbearable and yet she walked to him just to wrap her arms around him, he knew how stubborn she could be, but deep inside she was glad to see him again.

"You're late, idiot." She pouted as she received a patting on her head, the Butterfly girl enjoyed the warm sensation of his big hand.

"Haven't your heard?" He embraced her with his free hand, he nearly forgot how her petite body felt like. "Heroes always arrive late."

She giggled, bad idea, she fell to his knees. The injuries were grave and the medic team haven't arrived yet.

"Here. Aoi sent this." The night pillar handed Kanao the small bag full of medical supplies. He was glad that he asked for it. "Kanao, take Shinobu and get out of here. I'll handle this asshole."

The small hand of Shinobu held from his black cloak, refusing to let it go. The raven haired girl shook her head, struggling to stand up again.

She was injured but to fight that monster on his own was a nearly impossible task.

"You can't fight him alone. He's too strong." The insect pillar couldn't react, she was pulled from her waist and the next thing she felt was the softness of Hiiro's lips.

They were soft and sweet, like she remembers, like she loved them to be, Shinobu slowly melted into the kiss, grasping the black cloak of the night pillar. She wished for that long awaited kiss to never end. When they separated, desperate for air and heavily breathing, the smile from Hiiro appeared, that stupid smile.

"You're always telling me to don't do things, that I'm a pervert, to run away." For once Shinobu knew that the boy was serious, he was like a different person, like something inside him changed. "Just trust me and go."

"I won't forgive you if you die..." Shinobu whispered as a blushing Kanao who was a little jealous of the scene she just witnessed, asking herself if Tanjiro will do the same the next time he saw her, took her sister on her back, she was light and did not put up any resistance.

"Be sure to check her injuries and patch her up." The night pillar patted her little sister's head, as he smirked, he was glad that everyone was safe. "I'm letting my beloved Shinobu to you."

The pink eyed girl nodded as she began to run away from there, the top priority now was to find a safe place and heal her sister's wounds.

"My, my, you are letting my meal escape." Douma appeared from the hole in the wall, he was mostly unscathed, three lesser demons appeared and kneeled in front of him. He was seemingly enraged "GO AFTER HER!"

The demons rushed their way to the small girl carrying the insect pillar on her back, they were near the exit, but they will make it on time. The stinky demons did not expect to found the night pillar blocking their way.

He performed the shunpo just a second ago and he traveled that distance. The three soldiers from Upper Moon two, stopped for a second with doubt on their moves, he simply rested his sword on the ground, he will not wield it against weaklings like them. Who was he?

"Get out of the way!" The first demon exclaimed as he activated his blood skill. He transformed into a full protected demon, he can even turn into a ball, hard like steel. A perfect defense "Blood demon art: Armadillo!"

The second one was more an offensive type, his arms turned into a violent form, he used those blade like arms to rip and tear his victims. "Demon blood art: Death Scythe!"

The third one grew some bigger teeths, as his head became bigger, now he had jaws like a wolf and his eyes were more vicious than before. "Demon blood art: Steel Fangs!"

Before they could even react, the armored one was already dead. Hiiro's punch pierced through the armor plates and with a swift and powerful uppercut the head of the demon was cut off. The demon with blades on his hands reacted and launched a barrage of attacks against the golden eyed boy only to found nothing but air and dust.

Another uppercut came from the boy, disintegrating the demon.

The one with steel fangs was frightened enough to not move an inch, the demon could just see in despair when the tenth pillar launched himself to kill him, he was like a wild beast.

Shinobu witnessed everything, her eyes were wide open and refused to believe it. He annihilated the demons without his sword. How strong is he? What kind of training did he went through? Thousands of questions flooded her mind but more than her mind, her heart was racing and she fell a little more for him.

He is strong and cool.

She was glad that Mitsuri was not close or she would be clinging to her beloved Hiiro-kun. The insect pillar closed her eyes and smiled.

"You can do it, Hiiro-kun." After witnessing the new strength of the night pillar, she rested her head on her sisters shoulders and left it all on his hands.

As soon as he slayed the three weaklings, Hiiro took his sword and parried the heavy blow. Douma tried to get his back while he was focused on the lesser demons.

"Oh? You saw my true intentions?" The playful smile didn't bad enough time to appear on the Upper Moon face as the Hashira pushed him back and unleashed his breathing technique.

"Breath of the night. Third style: La luna!" The round slash was effective and did hurt the unpleasant man, but be only reached his body.

The blood dripped from the demon's torso as he tried his best to regenerate it, but for some reason he didn't found the task easy.

'Is he that strong? Who he is?' The frustrated monster analysed his foe, he discovered that the young man was different from every other slayer he had fought before. Hiiro had a different aura surrounding him.

"Who might you be?" Douma had no time to act nice around the man in black cloak. The first attack and his breathing technique were in a different league.

"Why should I told my name to the demon who tried to kill MY Shinobu?" The raven haired boy rocketed himself unleashing the second style of his breathing technique: the dusk impact. His strength was not something to take lightly yet even blocking with his fans and all the strength his body had, the second strongest Upper Moon received damage from the vertical slash attack.

"You!" The demon was cornered, he will unleash his full power to kill the demon slayer and now, yes, now he had thought of something that will hurt him really deep. "Blood demon art: Frozen Mist!"

When the Upper Moon revealed his own power, Hiiro's eyes were glowing, he was already prepared to clash against the demon, but seeing Douma producing ice and frost from his own blood and flesh was definitely not on the list.

"Wintry Icicles!" Multiple ice spears began to form behind the Upper Moon, he chuckled happily when the night pillar retreated at the sight of his powers. "I will not kill you, demon slayer-San. I will leave you with enough strength to see how... I DEVOUR THAT BITCH IN FRONT OF YOU."

The stakes were thrown to impale the golden eyed boy, his eyes were shadowed, not reacting to the attack. The icicle spears reached their target, exploding and creating a dust cloud.
Douma began to laugh hysterical as he hopped into the place were he would find the injured pillar.

Much to his surprise he only found a black katana piercing through his chest.

"I was planning on killing you quickly, but that thing about eating her." He twisted Zangetsu, the demon spat blood and fell to his knees, shivering in fear of the man in black cloak. "You will die slow and painful."