Adapt. // kny x insert m!reader

21 - MT. NATAGUMO, II.

In the process of watching, Y/N sensed familiar auras from further away. His aniki's, who felt like he was close by and what felt like Shinobu's, but it was way fainter. He still hid his presence though, watching as the demon threatened to kill Tanjiro slowly if he didn't apologise. Soon enough, it sent the first attack. Tanjiro went to cut the string, but the webs cut his sword into pieces instead. Thankfully, the burgundy boy managed to dodge the attack, but barely. Y/N didn't have to step in yet, thankfully. He wanted for the Mizunoto to gain some experience, even if it meant nearly getting killed. The demon sent another attack- Tanjiro wasn't going to be able to dodge that, but Y/N saw the box on his back open last second, a small girl that grew in size got out and threw herself in front of Tanjiro, saving him. The girl was clearly a demon, but she was protecting a human. It really shocked the Hashira. He found out through the conversation, between the demon and Tanjiro, that the girl was the burgundy boy's sister- their sibling bond amazed both the demon and the pillar. The only problem was that the girl was taking forever to heal- she clearly hadn't eaten any humans with that speed or regeneration. The child demon demanded for the demon girl, 'Nezuko' as she was called, to become his new older sister, saying that he would spare Tanjiro if he handed her to the Kizuki, but of course, the slayer refused, insulting the demon once again, after watching the demon's current older sister get cut up into pieces by him.

"It doesn't matter if you refuse, I'll just kill you and take her." The demon said calmly, but Tanjiro only got angrier. "I'll take your head off, first." The boy threatened, his tone firm. "Someone sure is mighty. Come and get me if you can." The demon said, moving his hair back to reveal himself as a Kizuki, a sinister smile appearing on the child demon's face. 'Lower 4, huh..? Could it be because of me killing that Lower 3? Maybe.' Y/N thought to himself, trying to weigh out Tanjiro's chance of survival. While thinking he didn't notice how the Lower Moon had stolen Nezuko and held her close. When he looked back, the demon girl was in the air, screaming in pain by the strings tightening around her limbs, drawing a lof of blood. Y/N sort of wanted to help her, but she was a demon, so he held back. The battle started when Nezuko passed out. Tanjiro got his breathing and emotions under control and assumed a fighting stance."Water Breathing: Tenth form; Constant Flux!" Tanjiro yelled out as he charged at the demon. He started cutting the strings sent at him, taking the demon and the pillar aback. Y/N already knew what this form did, having read about it during his research time at the Butterfly estate. He wanted to implicate it in his own breath style, but since he couldn't use force to his advantage, due to the nature of his equipment, he didn't manage.

Just as Tanjiro was about to cut the demon's neck, which he failed to cut earlier, the demon backed away and spoke again. "Say.. You didn't actually believe this was as strong as my strings could get, right?" The demon said, the strings started to turn red- it was his blood art. "Blood Demon Art: Cruel String Prison." Ths demon said, unleashing an attack that was impossible to dodge. Y/N was about to jump in, until Tanjiro suddenly cut the red strings- he used a new breathing technique doing so; one that Y/N had never seen, nor heard anything of, before. "Hinokami Kagura: Waltz!" Tanjiro yelled out subconsciously, proceeding to cut every string sent at him, to the point he was within the reach of cutting up the demon, but from what it looked like, he was about to get slashed at the same time. Y/N was about to prevent that, but once again, something stopped him. The demon girl had woken up and had unlocked her Blood Art. Her blood started to glow, eventually exploding and burning away all the strings on her and in front of Tanjiro, allowing the burgundy boy to cut the demon's neck and stay whole. "NOBODY CAB EVER SEVER MY BONDS WITH NEZUKO!!!" Tanjiro yelled out in anger in the process of cutting fhe demon's head off, which got flung off. Needless to say, the Cloud Hashira was left stunned. He was so stunned that he failed to notice the trick the Kizuki had pulled. He just watched as Tanjiro fell to the ground, panting heavily because of changing breathing techniques, not paying attention to the body that had stayed standing