AN: One potential result of the pillars meeting Tanjiro and Tanjiro reacting poorly to Obanai's rough handling of Nezuko, resulting in a demon who's conquered the sun and all the possible consequences from it. (Shinobu PoV)
Shinobu watched as Giyu tried to edge his way towards the Kamado girl without being noticed. He moved slowly and was careful to keep his steps light enough not to affect the gravel underneath his shoes, trying to ensure that none of his fellow pillars noticed him as he moved behind where most of them remained knelt in deference to Ubuyishiki. If she hadn't looked over to make sure Nezuko stayed in place once Sanemi jumped up into the house then she wouldn't have noticed his actions at all.
Though his face gave no hint to what he was thinking, his attempt to get to her said enough. Shinobu couldn't help but find his strange behavior far more concerning than the demon in their presence. As things were now, the demon was no true threat. Sanemi's marechi ensured that the demon would focus on him even with Ubuyishiki and his two girls so close, and the six pillars actively focused on the show would make sure their master and his children stayed safe if the demon did somehow take out the wind pillar.
"Leave him alone!" Nezuko begged.
A pillar who wasn't at the top of their games cost lives, and Giyu was acting fishy. He had never shown any indication that he had wanted to try to get along with demons, and had even denounced the idea just before they went to the mountain together. But now that she thought back, she realized he'd carefully worded his answer. She had asked if he had thought humans and demons getting along would be good, and he had said that as long as demons ate humans that it would be impossible. But if he, Nezuko, and the former water pillar weren't lying then the Kamado boy had never eaten a human, which would mean he saw no problem with Tanjiro's continued existence.
Giyu had always been easy to overlook because of how quiet and amicable he was, and Shinobu had thought he was a bit airheaded because of how uncaring he could act around demons but now she saw she had been fooled. He already had a bond with those two, and a deep one if he was willing to risk ostracization and his own health.
"STOP IT!"
Nezuko's scream made Shinobu glance up at where Sanemi was stabbing his sword into the box repeatedly. Tanjiro's blood seeped out of the bottom and stained the tatami mats underneath. Sanemi finally kicked open the box and held his bleeding arm out over it, allowing it to drip down directly on the demon before he jumped back a foot.
"Come on, then, demon!" Sanemi taunted, "Come and get your favorite human blood!"
He was always so loud. She didn't see the point in making so much noise, but Sanemi was still better than Kyojoru if only because he knew how to use his inside voice occasionally. Tanjiro finally began to emerge from his box and an even greater hush fell over the gathered audience. It was obvious the poor thing was struggling; drool dripped from around the bamboo in his mouth, veins bulged on his forehead, and he had clenched his hands into fists so tightly that blood dripped from in between his fingers because of his claws.
"TANJIRO!"
Her attention turned back to Nezuko just as the girl tried to get to her knees. Obanai shoved her back to the ground and Nezuko's chin hit the gravel hard, her top teeth going into her bottom lip and drawing blood immediately.
She wasn't quite sure what happened next: one second Nezuko had Obanai on top of her, digging his elbow into her back, and in the next second Tanjiro appeared and sent Obanai flying with a kick to his sternum. She glanced up and saw that Sanemi almost looked offended to be ignored by a demon, and when she looked back she saw that Gyomei was already moving to take care of Tanjiro.
"He's protecting her!" Giyu put a hand on Gyomei's shoulder, "He's already-"
"GYAAAH!" Tanjiro screamed as his skin began to sizzle and smoke.
Shinobu almost didn't believe Giyu's words, even though she had seen it with her own eyes. Tanjiro had emerged from the safety of the shade to protect his sister, but now he was screaming as he burned under the sun. It was almost sad to watch the way he crouched over her despite the pain, and the way Nezuko's eyes widened in horror and she struggled to raise herself up but was prevented from doing so by his body. His face and hands were affected first because of the direct sunlight, skin burning and sloughing off.
"Giyu!" Nezuko could barely be heard over her brother's screams, "COVER HIM UP!"
Giyu took off his haori and tossed it over Tanjiro's head and shoulders, "Shrink, Tanjiro!"
If it hadn't been for Sanemi choosing that moment to come out of the house and jump down onto the gravel, Tanjiro might have listened. But even though he couldn't see Sanemi do it he heard him and reacted to the threat by scooping an arm under Nezuko and picking her up outright, and then using his other to grab Giyu by his uniform and pull him close before wrapping that arm around him. Shinobu got to enjoy the utter surprise on Giyu's face for only a moment before Tanjiro launched them all into the air, Nezuko hollering and kicking her feet the whole way. Giyu's haori fluttered to the ground in the place they had just occupied.
Tanjiro landed twenty feet away and stumbled a bit, the difference in height making Giyu's legs buckle underneath him. He dropped Giyu there and set Nezuko down next to him before turning to face the grouped pillars with a glare. He crouched down some in preparation to launch himself at whoever came closest. And though Shinobu could still see blackened and burned skin, Tanjiro was healing.
The sun was no longer affecting him.
"What's happening?" Ubuyishiki asked in the ensuing silence.
His daughter answered, "Tanjiro ignored Sanemi's marechi blood and rushed to defend Nezuko when Obanai shoved her down and cut off her air supply. He seems to have included Giyu as something to protect, as well."
"Tanjiro has conquered the sun," the other daughter chimed in.
Nezuko burst into tears and tossed herself on her brother's back, beating at his shoulders. Tanjiro stumbled from her unexpected attack and turned to check on her, Nezuko not pausing in her tear filled assault and beating on his chest. Tanjiro looked to Giyu as if he could explain why his sister was acting so strangely, and all Giyu did in response was step forward and wrap them both in a hug.
"You idiot, Tanjiro!" Nezuko sobbed, "Thank the Gods you're okay!"
The past minute and a half, if that, had been a rollercoaster. Shinobu took stock of those around her: Gyomei was openly crying tears and praying over the fortuitous miracle, Mitsuri had gone over to Obanai and had him half in her lap but she was grinning wide in the siblings' direction, Obanai looked like he was contemplating thanking Tanjiro, Tengen was watching the scene carefully, Sanemi looked furious, and Kyojuro had a look that matched Mitsuri's. She wasn't quite sure what she felt about this development, but it seemed most of the others were pleased with it.
"We should kill him now before Muzan can get his hands on him," Sanemi declared.
Giyu positioned himself so that it was obvious that if Sanemi wanted to go for Tanjiro then he would have to go through him first. Shinobu watched in amusement as Nezuko's face appeared over his shoulder as she glared at Sanemi, the girl most likely standing on her tiptoes to do so. Tanjiro for his part had calmed down and was just watching everything, seemingly content to let Giyu posture for him.
"We could do that," Ubuyishiki agreed, but the smile on his face disappeared. "But think of the precedent that would set, Sanemi. After all, what makes Tanjiro special? Can you tell me?"
Sanemi had no answer, so he gritted his teeth instead.
"I do not know, either." Ubuyishiki's smile returned, "So if we do not know what makes Tanjiro special, then how can we be sure he is special? What if it is merely chance, and no other demon that could conquer the sun had gone out in it because of their fear? Or, if he is the only one so far, Muzan could still make more. Would we kill the humans we have worked so hard to protect out of fear? Would we start with the ones around his age, with similar backgrounds? Or perhaps we should kill Nezuko as well, since they're siblings?"
Tanjiro didn't react at all to the implied threat towards his sister, and Shinobu had to wonder at his mental capacity. Her fingers itched for her journal so that she could start writing observations, enticed at the thought of getting to run some tests on him. Was he capable of sensing killing intent? How many words did he know? Was it just because Nezuko had spilled flesh blood that he reacted, or would he have reacted if she had called for his help? What other abilities did he have? All questions she desperately wanted answers for.
"Tanjiro is not a victory for Muzan," Ubuyishiki continued. "Tanjiro is a victory for us. Despite having marechi blood waved directly in his face after being injured, he ignored it in order to protect his sister. That gave us our proof that he would not attack a human, but now he has given us so much more. If we utilize him correctly, then perhaps we can find a way to reverse Muzan's effects on humans. He is our hope, and we will not squander that to fear."
And that was that. Shinobu knew that to do anything against Tanjiro now would be counted as treasonous, and from the furious expression on Sanemi's face it was obvious he knew it as well. But there was nothing to argue against because their master was right: Tanjiro had proven he could fight against the draw of marechi, and killing him to stop Muzan from getting him was a stopgap at best.
"Nezuko," Ubuyishiki's sightless gaze spanned the garden. Nezuko stepped out from behind Giyu's back and ground her heel in the gravel so he could look right at her, "Despite this, there will be people who are unable to accept Tanjiro and the risk he poses. If you work hard to earn your place among our numbers and defeat the upper moons then others will be forced to acknowledge you and your brother's place here."
Nezuko bowed low, "Yes! Thank you, Oyakata-sama! My brother and I will do our best!"
"You may step back now, Nezuko." Ubuyishiki turned his gaze to where Shinobu knelt with most of the other pillars. "And we can begin the pillar meeting."
"It would be an honor if you allowed my girls and I to take care of the Kamado siblings at my place," Shinobu requested with a smile.
Ubuyishiki inclined his head and Shinobu clapped her hands together, a signal for the kakushi to emerge from wherever they had been hiding. One retrieved Tanjiro's box from inside the house and then a second joined him as he went over to the Kamado siblings. Nezuko looked to Giyu to make sure it was alright before she urged her brother back into his box, handing him off to the male kakushi once he was inside. Then she turned to Sanemi.
"You!" Nezuko pointed at Sanemi, "What's your favorite food?!"
"Hah?!" Sanemi let out a breath of pure disbelief, "What's it to you?!"
"Ohagi," Shinobu offered. She only knew because of how often Sanemi spent time in her estate healing.
"Shinobu!" Sanemi shot her a dirty look.
"Shinazugawa!" Nezuko got his attention again, "You get a pass for hurting my brother this time because I understand why a pillar would want to make sure a demon isn't a threat. But if you ever touch him again and he hasn't warranted it then I will rip your dick off, chop it into tiny pieces, put it in the center of several ohagi, and feed it to you. And it will be the best damn ohagi you ever ate."
Giyu looked scandalized by the time Nezuko was done with her threat, and even their unflappable master had raised his eyebrows up towards the end of it as if in surprise. Mitsuri, Gyomei, and Tengen were all obviously fighting off laughter. Sanemi scowled but Shinobu could tell he was impressed by her courage.
"Nezuko-chan!" Giyu managed to chastise with just her name alone.
"Sorry, Giyu-kun, Oyakata-sama." Nezuko apologized with a sweet smile and Shinobu decided she liked the girl after all, "I'll go now."
The female kakushi looked incredibly relieved and knelt down so Nezuko could climb onto her back, but then Nezuko paused and the kakushi let out an audible groan. Nezuko patted at her haori and then took something wrapped in cloth out of one of the pockets, going over to Giyu and forcing it into his hand. She then hugged him and pecked his cheek.
"There's onigiri in there," Nezuko told him. "Make sure you eat it before too long and take care of yourself, okay?"
Giyu muttered something too low for Shinobu to hear and Nezuko grinned at him. The kakushi that had been about to give her a piggyback rushed over to her and picked her up bridal style instead.
"Send my regards to Tamayo-san," Ubuyishiki said.
Nezuko looked at him in surprise and started to open her mouth to respond, but the female kakushi had had enough. She hoisted Nezuko up higher and then proceeded to sprint out of there as fast as possible, her male counterpart trailing just behind her.
And once Nezuko was out of sight it was like a dam broke, the pillars around Shinobu finally speaking up.
"Damn," Sanemi muttered, kicking at some of the gravel underfoot. "I like her."
"She has fire!" Rengoku laughed.
Tengen nodded, "Surprisingly flashy."
Obanai scoffed, "They still have a long way to go to prove themselves."
"It's lovely she cares about her brother so much," Mitsuri said with a far off expression.
"Yeah, I guess," Obanai relented.
"May those poor souls find happiness," Gyomei prayed.
"Who was she?" was Muichiro's impression of her.
Shinobu was given a gift today. Her impression of Giyu had been turned on its head, but one thing remained the same: he was still incredibly fun to poke fun at, and Nezuko had given her ample ammunition. She'd be able to ask Nezuko plenty of questions once she returned to her estate, but for now she was getting a thrill out of looking at the pink staining Giyu's cheeks. Once the meeting was over and Ubuyishiki dismissed them she'd tease Giyu until he finally broke and snapped at her.