Apathetic Demon slayer (KNY/Demon slayer x male reader)

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"Tanjiro! You little shit! Im trying to help you!" Mordecai barked, very clearly irritated that he was interrupted so rudely. "Now pay attention, because I'm bleeding a lot and light headed, yeah?!" 

"Right! Sorry, I was talking to myself!" Tanjiro apologised and started paying attention. 

"Now, blood loss has made me less sharp, so forgive me if I'm wrong, but as I pieced these papers together, the puzzle says that you need to make sharp, harsh breaths!"

"Thank you!" Tanjiro thanked and grinned. 

"Hurry! I'm getting lightheaded!"

"Vanish from my sight, you vermins!" the demon roared and started drumming even quicker if that was even possible. Mordecai yelled at the sudden rotation and nearly threw up out of pain as he landed stomach-first on a surface. 

"T-Tanjiro!" Mordecai yelled weakly. "Remember! Short breaths! Short breaths!!" he himself was doing longer breaths even though it hurt as if hell itself was torturing him. He needed to slow down his blood circulation to slow down the breathing. "I'll distract him! You get the head!" 

"Got it!"

"Breath of thunder, 6th form: Rumble and flash!" Mordecai launched himself, his blade sparking with electricity. Blue and yellow lightning crackled around the boy as he flew at the demon, multiple lightning flashed surrounding it. The demon looked around in confusion, temporarily stopping his drumming, only to soon realise that he had lost both arms to the lighting boy. 

Tanjiro was quick to follow. "Breath of water, 9th form: Water splash, chaos!" He ran at the demon, water following his footsteps. When he jumped, a large tsunami-like wave surrounded him. "Your blood demon art is very impressive!" he yelled before he cut the demons head off. Mordecai looked stunned, but mostly confused by Tanjiro's last comment. Sure, it was impressive and epic, but it was still a demon. The red haired boy fell to the ground, gripping his chest in pain. Mordecai was laying on the ground, pushing through the pain that was tearing through his stomach and piercing his lungs. 

"Kid..." the demon spoke. "Answer me... My blood demon art... is it really strong..?"

Tanjiro didn't answer for a while. "It was very strong" he eventually replied. "However, killing humans is unforgivable" he then pulled out an odd needle-type knife and threw it at the body with immense precision. There was a slight meowing sound, making the 2 boys turn to it. 

"Has that always been there?" Mordecai mused. He guessed not, as it looked unscathed. 

"Ah, you're here to take this to Tamayo-san. Thank you, please be careful" Tanjiro talked to it. The grey eyed boy wanted to ask who Tamayo was, but he was too weak. His grey eyes grew duller by the minute. The red head ripped off a piece of fabric from a curtain and pressed it over Mordecai's wound, lifting him up and helping him out. 

"Kiyoshi, Teruko!" Tanjiro called out and opened the door to reveal 2 screaming children throwing stuff at him. A book landed Mordecai square on the nose, making it bleed a little but thankfully not breaking it. "Woah! Why are you throwing things?!" Tanjiro whined. 

"Tanjiro san... Sorry, the drum disappeared so we panicked..." Kiyoshi apologised. 

"Thats alright" Tanjiro shrugged it off. "Teruko" he turned to the girl. "Do you think you can help Mordecai stand? He's lost a lot of blood and could pass out any minute, can I trust you with him?" he asked. 

"Why does the girl need to carry me, is it 'cause I'm small?" the brunette growled. 

"N-no sir!" Tanjiro exclaimed, honestly a bit intimidated. "I-its just that Kiyoshi-kun can't walk, so I'll need to carry him"