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 14: Tanjiro arrived at Tamayo's hidden clinic and Tamayo's willing to help Nezuko get better. But she turns out to be a much more stubborn patient than anyone thought!

The chase of Tamayo's cat was almost endless. Tanjiro felt like he was running forever. How could this little cat keep going? Strange question, but since it couldn't disappear, the answer was unknown. The cat had to keep leading the way to where Tamayo and Yushiro went into hiding next.

He kept running carrying Nezuko as gently as possible given he figured her entire body was in pain by now. Especially since she's now starting to cough up blood. He had to hurry. Her time might have been running out.

"Don't worry Nezuko… I'm sure we'll be there soon…" Tanjiro said looking down as Nezuko, who showed no change in her state. It was bad. But she was still alive.

He could feel his own body temperature rising again but this didn't matter to him. All that mattered was that Nezuko could be saved. He wouldn't stop for anything, even the stress-built fever that he had himself.

He really hoped they would get there soon. But he understood why it was far. Tamayo had to hide from Muzan. He was looking for her, the two demons they met on their meeting said as much calling her a "fugitive" and he couldn't let his only hope of saving Nezuko, not once, but now TWICE get found.

After some time from running, the cat finally came to a wall in the middle of what looked like a forest yet urban area. Tamayo was still a doctor so she had to take refuge in another area she could still do some work to not arise suspicion amongst the community.

Tanjiro was relieved as he then sat down. The cat looked at him looking confused.

"Sorry… I…I just need a moment to breathe." He said gasping for air. He was running for a long time and even if he had good training to keep his stamina up. He was low on sleep and a little sick and weak himself so this would probably push him to his limit.

The cat looked away and then walked towards the wall.

Meow

The cat disappeared. Its job was done leading Tanjiro to Tamayo's new hidden clinic.

After getting his breathing under control, Tanjiro looked down to Nezuko who was still doing badly but she was stable enough.

"Nezuko…we made it…we're at Miss Tamayo's place… You're going to be okay…" he said under his deep breathing.

Nezuko responded with just a small groan.

Soon a familiar voice could be heard from behind the wall.

"Well hurry up and get in here! Don't keep Lady Tamayo waiting!"

There was no mistaking that aggravated tone. Tanjiro sighed upon hearing the familiar voice belonging to the demon boy who stayed by Tamayo's side. And REALLY likes her…as he remembers that he read his diary.

Tanjiro let out a sigh of relief knowing he was in the right place. He sat up holding his sister as she breathes heavily down his shoulder and walked through the wall. Revealing a similar building to Tamayo's old one.

Yushiro was standing close to the entrance. His look of disapproval hasn't changed one bit. This made Tanjiro smile to himself as he walked closer to him.

"I heard from Chachamaru." Yushiro replied. "Your little sister's not doing well?"

"Chachamaru?" Tanjiro asked. "Who's that?"

Then a noise could be heard from below.

Meow.

Tanjiro looked down to see the Calico cat leading him at Yushiro's feet.

"Oh, so you do have a name." he said as he smiled at the cat to show his appreciation. "Thank you for leading us here, Chachamaru."

Then he looked back up at Yushiro to answer his question.

"My sister is very sick..." like clockwork Nezuko proved her condition with a small cough. Tanjiro frowned looking at her "Please… Is there anything Miss Tamayo can do to help her?" he pleaded.

Yushiro looked down at Nezuko in Tanjiro's arms. He sighed then turned around.

"Alright come on." He said as he opened the door to lead Tanjiro into the building made by Yushiro's blood demon art.

Yushiro came at the door and opened it repeating the same thing he said when they first met upon entering Tamayo's clinic room.

"I have returned Milady." He spoke.

"Welcome back Yushiro. Is Tanjiro here?" Tamayo responded standing by a medicine cabinet.

"Yes…I'm right here Ma'am." Tanjiro responded as he walked in, still carrying Nezuko.

"Tanjiro. Welcome back, good to see you're doing alright."

"Thank you. Nice to see you're well too. But…I have to ask you. Please…"

"I know. Here, let me have a look at her."

Tanjiro handed Nezuko to Tamayo. She gently cradles her and sets her on the bed.

Nezuko then opens her eyes among the scent of someone, not as familiar as her brother and also…not human. She looks up at Tamayo and starts growling. She saw Tamayo as a demon. The words Urokodaki implanted in her mind were confusing her. Was she supposed to fight?

"Nezuko, it's okay! It's just Tamayo!" Tanjiro frantically said seeing his sister start to lose control again.

Nezuko couldn't hear her brother. The high fever and Urokodaki's hypnotic suggestion were both swirling in her mind confusing her. She was too weak to move much but she was still in a feral position. Similar to a feral cat at a vet.

"Nezuko, calm down it will be alright." Tamayo said as she reached for her to examine her.

Nezuko grunted swatting her hand away from her.

"Why you little brat!" Yushiro yelled out in anger seeing this sight. Tanjiro looking in shock wanted to hold him back, but this wasn't Inosuke.

"Yushiro." Tamayo responded in a stern tone.

"Y-Yes…" Yushiro said in a defeated tone. "I apologize for speaking out of line."

Tamayo then looked back at Nezuko. She was used to this; she was just a little different than the human children that she usually saw as a doctor.

"Everything's okay Nezuko…" she said calmly. "I need to look you over to give you medicine…"

Nezuko continued to struggle as Tamayo calmly looked her over. She was too weak to truly fight back so she looked no different than a small toddler throwing a tantrum.

Tanjiro looked at Tamayo with a worried expression. "Will she be…alright, Miss Tamayo?" he asked.

Tamayo looked up looking at Tanjiro as she still held Nezuko down, who was still grunting growling and struggling. She smiled serenely.

"Just leave it to me."

Tanjiro breathed such a sigh of relief that was immeasurable. The biggest weight of anxiety was lifted from his chest the minute he heard his sister would be okay.

"Oh…thank…goodness…" Tanjiro said as he began to sob.

Tamayo was having a hard time with Nezuko so she had to ask Yushiro for help.

She instructed Yushiro to get a specific type of medicine that was located in the basement area of the house. She said it in a coded number so Tanjiro had no idea what they were talking about. He nodded and was out the door. It didn't matter he was both worried and embarrassed by Nezuko's behavior. She was fussing even louder and even started roaring a little bit. And the worst part: she was NOT muzzled.

"Do you need any help?" Tanjiro said. "Maybe I can calm her down…"

"Best to not." Tamayo stated. "She may bite you if you're not careful and we cannot let that happen. Don't worry, I can handle her like this."

"Right…" Tanjiro said as he sat on the floor beside Tamayo watching his sister struggle in the doctor's arms.

Yushiro then came back with a box and set it beside Tamayo.

"Thank you Yushiro." Tamayo said.

Nezuko began throwing even more of a fit. Tamayo continued holding her down.

"Yushiro…" she said looking to him.

"Yes Milady!" Yushiro responded.

Like clockwork in Tamayo's place, Yushiro gets the needle out and injects it in the fluid to gather the medication. Tanjiro watched intuitively before he ended up suddenly sitting down. Collapsing from his own exhaustion after all of this. He tried to stay awake thinking he would eventually be needed.

"Okay I got it." The demon boy responded.

"Okay Nezuko, time for your medicine." Tamayo stated to her.

Nezuko would not comply and continued to have a fit. Tamayo still had a very hard time restraining Nezuko enough to calm her down. She needed both hands to restrain her. Suddenly Nezuko stopped and began coughing again. This time she ended up vomiting, even if she didn't eat, she still let out any toxins this virus had given in her body. Along with some more blood.

"She's getting worse, we must hurry!" Tamayo stated letting her go to let her finish her business.

"Nezuko!" Tanjiro shouted deeply concerned upon this sight.

Tamayo then saw an opportunity to grab the medicine from Yushiro and take Nezuko's arm. Nezuko stopped spitting fluids and looked back up growling. But Tamayo was able to hold her arm down and successfully injected the needle into it.

Nezuko winced in pain as the needle was jammed into her arm. The fluid was pushed into her vein. Nezuko whimpered slightly and then growled again.

After the needle was taken out, Nezuko lunged herself at Tamayo and ferociously bit her hand.

Chapter 14 done! Nezuko got her medicine but has lost control and bit the hand that tried to help her! Yikes! What's going to happen now!?