Author's Note: Hiii its me again! I'm back after a while with a new story! This one's based Demon Slayer Kimetsu No Yaiba. I recently got into the series and I fell in love with it. But I noticed there were NO sickfics of it on here. So to my disappointment I thought, okay time to take matters into my own hands here! And after a few months of thinking, I got this interesting idea. And I'm aware that the manga confirms that demons can't get sick, but hey Nezuko's a unique demon so maybe she's an exception) It'll be a bit more intense than my usual fluffy fics, this one has a bit of a story arc to it. As usual I hope you enjoy and I hope I do these characters justice or get their personalities right in the writing because I've only been into this series for a couple months.

This may also be my longest fic yet. I have some plans for this one c:

Chapter 1 is just the prologue. Tanjiro and his demon slayer team were on their way to another a mission until it rains. So they have to take shelter for the night.

It wasn't too long after Tanjiro set off on his quest to find a way to turn his now demon sister back to a human again. Along the way he learned new demon slaying skills, met some reliable friends and allies, and earned the trust of the Demon Slayer Corps Organization. He often went on demon slaying missions with his companions hoping to save others from demon attacks or run into one of the Twelve Demon Moons, Tanjiro and the Corps' biggest target priority. They recently finished off 2 of the lower moons, but sadly they lost one of the Demon Pillars and a reliable friend in the process.

After they had recovered and went on missions again, this mission was just another case to slay a demon in a village to the west, as his Kasagi crow kept screaming in his ear multiple times. And although it may not have been one of their targets, the corps was still testing them and giving them small jobs for a while and to train some in the process.

Getting to their destination would probably take another day and the sun was going down. It was also starting to rain. Luckily, there was an inn nearby, hopefully with the wisteria crest on it. Meaning they got to stay in free of charge. It was just one night, and everyone was tired. Tanjiro was joined by his two friends, Zenitsu and Inosuke. The three of them had been a team since they met, even if the meeting was more than a little awkward. Tanjiro also carried a wooden box on his back, containing his little sister, whom had to be protected during the daylight but was quite a fighter during the night resulting in a powerful ally. So, there were actually 4 people in total.

"THE MISSION IS TO THE WEST. TO THE WEST!" Tanjiro's crow continued to squawk in his ear noticing he was heading in the wrong direction.

"I know I know! But it's raining and if we keep going at this rate, we may catch a cold. Can't we rest until the rain stops?" Tanjiro pleads to his crow, covering his other ear in annoyance.

"BAH! You're just weak! This rain is nothing to me! I am invincible!" the boar masked boy known as Inosuke said beating his chest and running around in circles for no reason.

"There he goes again. Why does he want to make everything into a challenge?" Zenitsu sighs looking at his bulky colleague running around shirtless with his boar mask intact. He truly looked absurd. "If anyone's gonna catch cold, it'll be him."

Tanjiro sighed shaking his head slightly looking at Inosuke and turned back to his nagging crow. "See? If any of us get sick, we won't be at 100% to do our job. Can't we rest just this once? We'll leave the minute we awaken."

The crow mulled it over for a moment and then spoke.

"VERY WELL! REST FOR NOW BUT NEXT DAY BACK TO WORK!" the crow said. "STAY AT THE INN LOCATED NORTH ABOUT 10 MILES FROM HERE!" then it flew away.

Tanjiro nodded and watched as it flew away knowing he'd probably get a lecture for this by the demon pillars when they returned. But because of his older brother-like nature, he felt responsible for his team and knew continuing the walk in this weather would prove to do more harm than good. He turned to face both his friends.

"Alright, we're headed to the inn nearby you guys." Tanjiro announced.

"Oi Monjiro! Who the hell died and made you the leader!?" Inosuke barked back.

"Jeez, aren't you tired at all boar head?" Zenitsu asked. "I know I sure don't want stand out here in the rain to catch a cold." he brushed his wet golden hair back a bit.

"I ain't tired at all! I could go on forever!" he responded with confidence. "And I don't get sick! Only the weak catch cold in the rain! You're just not strong enough!" he continued boisterously.

While Tanjiro did believe him, he didn't want Inosuke to stand out in the rain alone, so he tried something else to get his attention. He remembered back at the first inn the trio stayed in, he seemed to be fond of the food there. He then turned to face Inosuke again.

"Fair enough, you are strong. But I bet you're hungry too." Tanjiro added. "We've been walking all day and none of us have eaten at all."

Inosuke then stopped and looked down listening to his stomach as it growled loudly. He let out a loud frustrated groan.

Tanjiro smirked noticing that got his attention as he continued "We might get our shrimp battered again. Deep fried and golden brown…" It was as if Tanjiro had the wild boy all figured out. He did love to stuff his face when given the chance.

"ARRRGH FINE! But you better not be lying Kentaro!" Inosuke said pointing at him as he stomped off past the redhead and blonde in a huff.

"Good grief. He still can't get it right." Tanjiro said looking at him awkwardly. It was as if he wanted to purposely get his name wrong at this point. He then felt a small tug on his sleeve and turned around to see his other friend Zenitsu looking to him.

"Come on Tanjiro, we'll lose sight of him at this rate." Zenitsu said before he shivered and let out a small sneeze. "…and it's cold out here…" wiping the snot dripping from his nose with his sleeve.

"Right. Let's go." Tanjiro said as he and Zenistu followed behind Inosuke, who clearly had no idea where he was going.

"Hey Inosuke! That's the wrong way! The inn is this way!" Tanjro called out.

"I knew that! I was just testing you!" he responded angrily running over to the direction where Tanjiro pointed right past both of them.

"Jeez, does that ego of his ever take a day off?" Zenitsu sighed looking at him run.

Tanjiro laughed as both of them followed behind him as they headed for the inn to rest for the night before their next mission.

That's it for chapter 1! Yeah nothing really happens yet. But things will start to go down sooner than you think! ;)