Mitsuri followed Tanjiro around the outskirts of Asakusa in zig-zagging, retracing and circling patterns for almost the full two hours. Eventually, though, they made their way inside the city and began searching for the izakaya Yushiro had asked them to meet him at.

Doing so without asking directions (they were invisible) turned out to be incredibly difficult. As they didn't want to leave a trail of any kind, they ended up asking a man focused on closing down a stall in the general area before he turned around. He pointed in the general direction and began to explain but cut off when he finally realized no one he could see was there.

Still, his instructions helped out immensely and they managed to show up only a couple of minutes late. Yushiro stood outside of the establishment looking utterly murderous, tapping his foot impatiently. The moment he saw them, he shouted at them.

"You're late!"

"We're so sorry!" Tanjiro said, simply bowing. Mitsuri huffed. They were late because they were trying to keep his beloved Tamayo-san safe. He should be more grateful. However, she didn't really want to start a fight right now, so she bowed next to Tanjiro and said nothing.

Then her stomach growled and she looked away, not wanting to see the judgment from the other two.

"Mitsuri," Tanjiro started, but Yushiro cut him off.

"This way. Lady Tamayo is looking at your sister now," he said as he stalked off down the street like it had personally offended him.

"She is?" Tanjiro asked, eyes lighting up.

"Of course. Now hurry!" Yushiro said over his shoulder.

So they followed him, taking a still very convoluted, circular route before Mitsuri saw the demon boy walk through a wall. She blinked. Tanjiro didn't even hesitate to follow, though, so she took a deep breath and jumped through. On the other side, she paused and looked back, a little astonished at the same brick wall she'd seen on the other side.

Well. That was cool.

She loved it. Even if it had been some sort of trick done by the rude boy. It was funny, normally she found quiet or protective traits endearing, but something about Yushiro rubbed her the wrong way and she didn't know why.

Mitsuri then turned around to see an enormous mansion with Western style features. Her mother had always hated that style, preferring the traditional Japanese houses instead. What a shame, because this was lovely. Not that she didn't love her own home, but still.

"Oh, that's so amazing!" she exclaimed.

Tanjiro smiled at her. Yushiro scoffed. Mitsuri ignored them and kept whirling around, taking in everything she could see.

Once they reached the front door, Yushiro turned to them, holding out his hand. "I want my papers back."

Mitsuri didn't roll her eyes (that would be rude) but it was a near thing. She did place the paper gently in his hand, as did Tanjiro. The demon boy simply nodded in satisfaction and placed the papers in a pouch at his waist before he turned and walked inside. Tanjiro and Mitsuri followed.

Once inside, she closed the door behind her and turned to see a very interesting set-up. Long, narrow internal hallways connecting rooms instead of multiple rooms that could be turned into long passage ways if necessary. Somehow it felt stable and she found she rather liked it. Maybe she'd get a house like this one day when she finally got married.

Tanjiro and Yushiro had already headed down the hallway and towards one room in particular. Yushiro went to open the solid door, like the one at the inn instead of the typical wood and paper doors she was used to. It didn't open. Huh.

"Just a moment," a voice called from inside. Mitsuri didn't recognize it. She did hear a conversation, though it sounded too quiet to make out specific words.

After a couple of seconds, Mitsuri heard someone approach the door. It opened to reveal a very pretty woman in traditional Japanese clothing. Yushiro bowed immediately.

"Tamayo-sama!" he said, and honestly seeing him like that gave her the first truly positive impression she'd had of him all night. It was obvious he was completely devoted to this woman. While she already thought he took it too far, it was still kind of adorable.

The woman – Tamayo – opened the door further.

"I am Tamayo," she said with a bow. No family name? Interesting. Then Mitsuri realized she'd introduced herself for her sake because Tanjiro bowed and said:

"It is good to see you again, Tamayo-san!"

Mitsuri didn't squeak, but she did jump a bit and then bowed herself.

"Kanroji Mitsuri!" she exclaimed. "Nice to meet you!"

"A pleasure to meet you, Kanroji-san," Tamayo said with a soft smile.

Out of the corner of her eye, she saw Yushiro scowl, but he didn't say anything so she didn't comment.

Then Tamayo's eyes fell on the body Tanjiro had been carrying for the last two and a half hours. "And who is this?"

Tanjiro glanced at Mitsuri, suddenly looking nervous. Mitsuri was torn between being annoyed and cooing at his cuteness. This was his contact. She'd let him take the lead to see exactly where this would all go (partially because she was curious and partially because Ubuyashiki-sama wanted to know as well). So she nodded grimly and hoped he'd interpret that however he needed to.

He returned the nod, looking firmer now, and took a deep breath as he turned back to the woman standing in the doorway.

"This is Akaza… also known as Waxing Moon Three."

Tamayo's eyes widened a little, but not in surprise. Mitsuri wasn't sure what made the woman react, but it wasn't that, she was sure.

"So, it's true," Tamayo said reaching out to touch the demon, but pausing before she made contact (funny, her hands looked completely normal, wasn't she supposed to be a demon?). "Nezuko-chan says you are positive he will not wake for a while yet and Muzan can no longer sense him?"

Tanjiro nodded, this time more firmly than before.

"How do you know that?" she asked curiously.

And the nervousness from before returned, although he tried to hide it. "I don't know," he said.

Tamayo's eyes widened again, this time it was out of surprise, Mitsuri thought.

"Interesting. Please, come in. Nezuko-chan says she wouldn't mind if everyone heard my diagnosis."

Mitsuri didn't like the sound of that. Apparently neither did Tanjiro.

"Nezuko! Is she okay? What's wrong?"

"How dare you demand such from Tamayo-sama!" Yushiro cut in angrily.

"Yushiro," Tamayo warned.

Immediately, the boy straightened, looking the perfect picture of an obedient assistant. "Yes, ma'am!"

Tanjiro had ignored the entire exchange, heading over to Nezuko who stood in front of a chair she'd likely just been sitting in near a corner of the room.

"Nezuko! Are you alright?"

"I feel fine, Nii-chan," she assured her brother.

He looked over at Tamayo. "Is she alright?"

Tamayo smiled. "Perhaps you should lay your prisoner down on the couch and we'll discuss it?"

Tanjiro blinked at her, then seemed to remember he still carried a demon on his shoulder.

"Oh, right," he said, looking around and finding a couch against a nearby wall. He walked over to the couch and gently laid his burden down. Then he turned immediately back to the doctor.

"Tamayo-san?"

She smiled again, expression fond.

"Nezuko is fine, and as far as I can tell, completely human."

The demon slayers in the room let out a collective breath of relief.

Then Tanjiro seemed to recall something and bit his lip, looking over at his sister. "But, what about her hair? It wasn't like that before, but when she becomes a demon…"

And suddenly Nezuko looked worried again. Mitsuri hurried over to hug her.

Tamayo walked over to one side of the room where a long table had been set up against the wall. On it sat glass beakers and bottles and containers of all kinds. She took a small glass slide from under a strangely shaped piece of equipment. Was that one of those expensive Western microscopes she'd heard about?

"This is a sample of Nezuko's blood. After looking at it under a microscope, I'm seeing no trace of typical demon cells or even the modified demon cells I found in Tanjiro's blood stream."

Mitsuri heard a 'but' in there…

"However, I did find something… unusual."

The three demon slayers exchanged worried glances as Tamayo continued.

"My eyesight is better than a humans, and I can see many things. I can see what are called white blood cells – this is new research from the west. From my own research and what I've been able to read about when it comes to new science, they are cells that are altered when the body is diseased. They are, essentially, the method our body uses to fight off diseases.

"Nezuko has two kinds."

She paused, letting that sink in. "What's more is that they are coexisting in the same body. Because I do not have a sample from before yesterday, I cannot tell if she had them before, or not, but… the second kind of cells that I have not found in any other human, are fewer in number and, most certainly demonic in nature."

Mitsuri felt her stomach drop, but Tamayo looked thoughtful for a moment.

"Or, should I say, anti-demonic."

Wait…

"What?!" Mitsuri, Nezuko and Tanjiro all yelped at the same time.

Tamayo shook her head. "I couldn't begin to guess as to how this happened, but… I have reason to believe that Nezuko is, at the very least, resistant to demonic cells – and thus a demonic transformation."

Mitsuri just kind of stared in flabbergasted shock. Nezuko didn't seem much better. Tanjiro spluttered like he didn't know what to say, and even Yushiro looked surprised.

"But… she almost transformed just days ago," Tanjiro said, looking like the very words pained him.

Tamayo nodded. "I believe that is part of why she has these cells – although I cannot be certain. You targeted the cells and burned them out of her. Combine that with whatever has led your family to be able to resist them in previous lives and I believe that made a sort of anti-demon cell. They're similar enough, though, that I believe that is what has given Nezuko-chan her mildly demonic traits, such as the craving for meat and the tips of her hair."

Mitsuri wasn't sure how to feel about the fact that Tanjiro seemed to have explained everything about his 'time loops' to this doctor as it likely happened before the Pillars knew. After all, being annoyed and maybe a little jealous was not rational…

Then again, she didn't think any emotion was truly rational. Didn't stop her from feeling them anyway.

She found it odd that her mind focused on that and not on the fact that Nezuko might be able to resist becoming a demon if a Waxing Moon or Muzan ever found her again in the future. Did that mean…

"Yes," Tamayo said, as if reading her mind. "I think that Nezuko is the key to reversing demonic transformations in the future."

Everyone in the room just kind of stared at her for several seconds in shocked silence.

Then:

"Ehhhh?!"

xXx

Tamayo asked to draw a fair amount of Nezuko's blood after the conversation and diagnosis so she could look at it. She assured them she'd make sure to do so in relatively small increments over the coming week, but Nezuko didn't seem to particularly mind.

"If I can help to create a cure for demons, of course I'll do it," she said, determinedly. Tamayo seemed very pleased with her response. Likely due to jealousy, Yushiro just kind of sulked around and glared at everyone after that. Tanjiro would watch him with a fond, if exasperated smile. As long as the demon didn't intend to harm any of the demon slayers, the Sun Hashira was more than willing to sit back and not intervene.

That night after they'd discussed what to do about Nezuko, Tamayo decided to examine Tanjiro. She didn't do much more than confirm what he already knew, though. His strange demonic cells had multiplied in his human form and it would not be a good idea to try and eat human food any longer. He'd known she would say that… but it still hurt.

"I'm sorry, Tanjiro-san," she'd said softly.

"It's fine. Thanks," he'd replied with a forced smile. She'd frowned at him.

"You don't have to like it, you know," she said. "This would make anyone upset."

She wasn't wrong… but he still hated it.

"It's who I am," he'd finally replied. "And I have to cling to it, because I won't lose that too."

She hummed but didn't push it. He appreciated that.

He also let her take a large amount of blood to study and no small amount from Akaza either. They ended up moving him to the cell in the basement, knowing full well that it couldn't hold a Waxing Moon if said demon didn't truly want to be held, but it was the best they could do.

Besides, Tanjiro wanted to talk to the guy. He was different, somehow. Tanjiro could feel it. So Yushiro put a special vision paper that would make him think he was in a different place – although he didn't say where exactly.

It turned out to be unnecessary as he remained asleep.

Unfortunately, once Tanjiro dropped off, so did he.

xXx

Tanjiro sat on a tree stump, contentedly watching his father dance the Hinokami Kagura. Even if he knew it was now a sword form – a breathing form – it still moved and flowed like a dance. He loved it.

Sighing happily, he snuggled down a little deeper into his scarf, bringing up his hands to blow some warmth into them. As soon as he saw them, though, he froze.

Claws.

He had claws.

His heart stopped and he looked around. Was he in Enmu's dream again? How?!

He stood, about ready to panic, when he felt a hand on his shoulder. His body stiffened and he looked up to see the empty circle of torches standing in the snow. His father was nowhere to be seen.

"Tanjiro," a very familiar voice said behind him. Almost immediately, he felt his shoulders slump, half in relief, half in shame. He didn't say anything. One good thing about the loops had been that his father would never see him as a demon.

"Otou-san," he whispered through fanged teeth.

"Hold your head high."

Tanjiro blinked, eyebrows furrowing in confusion. What? "Why?"

"You are willing to do so much to save your mother and siblings, especially now that I cannot be there. It is not an easy life that you have chosen, but it is an honorable one – even if it has such dire consequences."

Tanjiro felt tears come to his eyes.

"I hate this, Tou-san," he whispered. "I feel like I'm losing – like I can't win. And it's so hard to look everyone in the eye after… after what happened in the last loop. He… he made me do so many horrible things. He made me kill people – demons, slayers and civilians. H-he made me eat…" and he still couldn't say it aloud. But he knew his father knew what he was speaking about. "And part of me still enjoyed it, still liked the taste.

"How can you say I'm not a horrible person? A monster."

"Oh, my son," arms came around his shoulders, strong and supportive and so, so warm. Tanjiro cried more. "You always hold yourself to such impossible standards. Know that I believe you have done the best you could with the cards you were dealt. I wish you hadn't been made to go through such horrific experiences. But you weathered them and have managed to do what no one else could. No matter what else happens, know that I am so, so proud of you."

Another loud sob escaped his lips and his knees gave out on him. His father's strong arms didn't let him go.

"You should wake up soon, though."

He didn't want to.

He really didn't want to.

"The demon you brought with you is waking," his father whispered. "You will never forgive yourself if you are not there to stop him from hurting someone, so I am here to ask you to please wake."

Yes, Tanjiro had known that somehow, even if he'd only acknowledged it just then.

He took a deep breath and one final look around the clearing before nodding. "Okay, Tou-san," he whispered. Then, without looking, somehow knowing that doing so would end the illusion, he whirled around and threw his arms around the figure there.

"I love you, Tanjiro," his father said, patting his head as he snuggled into the old, familiar haori. "I love your siblings and your mother… so much. But I don't want them to come meet me before their time. You've done such a wonderful job protecting them… please, give yourself some credit.

"And please forgive yourself."

It was because his father asked him – and for only that reason – that he nodded. His father never pleaded… not like this. He… he wasn't sure he could hold to that promise, but he could try.

The hand petting his hair stopped and patted it instead.

"Good. Now, go. Simply will yourself to wake."

Tanjiro held on tighter for just a moment before he nodded and let go.

He opened his eyes to a familiar room in Tamayo's house – the one he was normally put in if he didn't recommend anything. Then he sat up, wondering how long he'd slept and trying to hold onto what he could remember of the dream he'd only just woken from.

It had been a nice dream, for once.

That's when something twinged on his senses and his breath caught in his throat as he looked towards the direction it was coming from… to the right and down.

Then he climbed to his feet and strode towards the door.

"Akaza…" he whispered under his breath.

xXx

AN: What can I say? The 'family from the afterlife' scenes were some of my favorite in canon. LOL :D

So yeah, more hints, more thoughts, more development... hope you like it. :)

Discord: discord. gg/EVUrHMd4za (no spaces)