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Chapter Text

This forest was creepy as shit. It felt like...it was alive. He could constantly hear moving, crawling, eight-legged demons EVERY-FUCKING-WHERE. But he stayed strong. He had to find Nezuko and Inosuke, but more importantly, he had to find Tanjiro.

'So I can kick. his. ass for abandoning me in this HELL FOREST!!!!' 

He sighed and listened. Yeah, he regretted doing that and the demon he saw. That nightmare fuel was the last thing he saw as he passed the hell out. And wow as much as he loved dodging spider after spider, he didn't.

None managed to get him, because he heard them long before they even decided to move. His mind was filled with the words of his gramps, memories of his childhood. 

That's when he heard the sound of fighting. A loud fight and he heard...Nezuko? And...and...TANJIRO. He was in trouble. And that was all he needed. The demon he was facing took off in the air and Zenitsu wasn't far behind. Powered up and pissed off. In a beautiful flash, he killed the creepy bastard and his little army of mini bastards in one fell swoop.

He let himself fall before kicking off the suspended house and took off in the direction of his friends. After all, Tanjiro couldn't die.

' I HAVE TO KILL HIS ASS FIRST.'

Tanjiro was far from having fun, as young as this demon was, he was powerful. AND MORE IMPORTANTLY, HE SHOULD BE POWERFUL AND DEAD. HE SLICED OFF HIS FUCKING HEAD! 

Haha...nope.

That little shit lowered his head down by his threads. “You thought you’d defeated me? Poor kid. Did your pathetic delusion bring you joy? I cut off my head myself with my own threads…before you could cut it off. Enough. I’ll kill both you and your sister. I have been this enraged in a long time.”

The slayer said nothing and weakly tried to crawl to his motionless sister on the ground. The young demon slowly trekked after him holding his head.

“But I wonder how you didn’t get burned. Me and my threads were the only things that were set ablaze.” Twisting his head back on, his face was contorted with rage.

Tanjiro didn't respond. He didn't look back. He focused on desperately crawling after Nezuko. Everything hurt. It burned. But he just breathed and didn't stop.

“I don’t know if it’s your sister’s power, but thanks for getting me enraged.” He violently stretched out his blood art-infused threads. “Now I can carve you up without regret.” The pissed-off demon narrowed his eyes. He sounded so calm but was obviously pissed off beyond belief. 

Tanjiro tried to keep crawling but eventually couldn't move his limbs. He could only lay there and not panic as the blood art surrounded him. It was over.

Suddenly he smelled something intense. Powerful. But still strangely comforting and, more importantly...familiar. 

'Thunder and...peaches?'

It took an absurd amount of energy but he managed to glance up. He saw gold, then lightning, then white shocking eyes, and finally....

"Zenitsu...."

He watched amazed as Zenitsu darted down to them like a streak of lightning. He smelled his rage, determination, protectiveness, and....sorrow. He then smelled fear and looked at Rui, who finally saw Zenitsu. It felt like time slowed down. He could see the horror in Rui's eyes when he realized he couldn't dodge in time. It was over but this time, for HIM.

Zenitsu was getting closer to the sound, he could hear it. He heard Tanjiro making pained, strained noises as he struggled to breathe. He heard his muscles practically screaming in agony.

'Poor Tanjirou, I know it hurts, I'm sorry.' 

He soared higher in the air to get a better feel of his surrounding. Finally, he pinpointed three figures. One motionless on the ground with muffled breathing, Nezuko. Another one the lying on the ground, judging from their sound it was Tanjiro. Meaning the last, a few feet from Tanjiro was his target. It was the demon.

So switching his footing in the air, he immediately bolted down ready to strike, while the demon didn't notice. Only to freeze. Zenitsu finally heard his sound.

It was heart-wrenching.

Time seemed to slow down, he was practically faster than it anyways. He processed this demon's sound. Processed his story. It was gutwrenching. Plagued with unbearable sorrow and loneliness.

'So much pain and anguish.' 

It was the saddest sound, he's ever heard, and it shook him to the core. Sheathing his sword, he went for a different approach. He was too close for the demon to attack, so instead, he opened his arms.

Soon, he had an arm full of demon and broke his concentration on his attack. Twisting his position to balance on the ground, Zenitsu continued hugging the young boy. He heard the confusion in his sound and felt the little one twitch. He didn't know what to do. He eventually growled and shoved the blonde away. 

'A hug? A HUG?!' Rui figured he was considered evil, but this person was beyond cruel! Who tries to emotionally manipulate a little kid in order to lure them to their death? A fucking MONSTER. Yeah, he was PISSED and far from in the mood for this bullfuckery. AND WHY WERE HIS EYES SHUT!? DOES HE THINK THIS IS A GAME!?

"I don't know what kind of sick and twisted game you're playing at, but I am NOT FALLING FOR IT!" Launching a barrage of attacks at the blonde using his blood art, Rui aimed to kill. The slayer took it in stride, blocking and dodging, but never attacking.

'WHAT IS WRONG WITH THIS WEIRDO!? WHY ISN'T HE FIGHTING!?'

He was frustrated and so angry. Mostly because...he wanted to feel that hug again... He could feel tears sting his eyes, but refused to cry. Not in front of HIM. He wouldn't give this monster the satisfaction of enjoying his pain.

"DAMN YOU! FIGHT YOU, COWARD!"

Every time.

EVERY DAMN TIME.

EVERY SINGLE FUCKING TIME, he got close, he showed affection.

Was it pathetic to say he...enjoyed it? That he liked it? How long has it been since he felt genuine affection? How many months or years has it been since he felt true love and not fear? He felt his resolve crumble. It scared him. Terrified him. 

Zenitsu cracked Rui's walls every time, he could hear it. Every hug. Every pat. Every smile, meant something. The web around his heart slowly fell apart. When he started unleashing the truly deadly attacks, Zenitsu finally spoke up. "I WAS ALONE LIKE YOU!"

Rui froze mid-attack and stared at him, confused.

"I know how you feel....I-I'm an orphan....I've been abandoned, manipulated, robbed, and had my heart smashed over and over and over again. Practically, every time I opened up. Every time I tried to give my heart to someone. Let them in...I felt nothing but agony. Except for two times. When I met my Jiji and when I met Tanjiro...he was so unwaveringly kind and gentle. He gave me a chance. He gave me hope."

Rui glared in anger. "What are you rubbing it in? Mocking me?! Who would be kind enough or more realistically foolish enough to give me a chance?! There's kindness, and then there's naive idiocy!" His next attack was huge and undeniably deadly.

Zenitsu once again sheathed his sword.

"Then call me a foolish idiot."

He simply held open his arms as the attack came for him. He heard the rather than seeing it. Honestly it was scarier than seeing it coming.

Tanjiro practically held his breath in fear and tried desperately to move. "Zenitsu...no...MOVE GET OUT OF THE WAY!!!!!!!"

Zenitsu never wavered. He never faltered. "Give him a chance Tanjiro... as you gave me..."

Tanjiro shut his eyes as tears fell. But he heard nothing... Looking up, he saw the attack fade mere inches from Zenitsu. Fatally close, but the boy never reacted. Tanjiro couldn't even smell fear.

Rui could only stare at the brave boy amazed. "What if I hadn't stopped it?"

The blonde responded immediately. He didn't miss a beat. "Then I would've died."

Rui frowned, "You would've died over a demon? A monster? A killer?"

The blonde shook his head, "I would've died over a lonely boy looking for the family he deserves. Looking to end his loneliness, his pain, the aching in his very being. Looking for somewhere to be happy and belong. And that is worth dying for."

Rui felt his heart beat. He felt the air in his lungs. He felt...alive.

Demonic eyes met golden eyes for the first time. They were warm and gentle. Like the sun. So so kind. Rui blinked as tears fell. Tanjiro and Zenitsu watched his eyes go from demonic to a humane, gentle blue. For the first time, they saw the boy underneath. Or at least Tanjiro did. Zenitsu always saw it.

The blonde smiled and once again, held open his arms kneeling down a bit. The boy stared for a moment before he ran into the hug. It was everything he dreamed of. It was soft, warm, loving, and real. Finally the emotional dam burst. Feelings he thought he lost so very long ago.

Zenitsu simply comforted him through it. He understood the emotions all too well. "Tell me your story." The dam broke and he told the duo everything. He wove a story of tragedy. Being born sickly, being fooled by Muzan (without saying his name, of course, he's no idiot,) his change, his parents, the new family, everything. By the end, he felt light. For the very first time, he felt free.

Smiling he looked up at Zenitsu with curiosity. "What's your name?"

"Zenitsu Agatsuma, your new big brother!" The little demon lit up like the stars and the blonde hugged him again. He couldn't resist...he was too cute!

"My name is Rui Ayaki."

They felt two more sets of arms hold them. Turning, Rui saw Nezuko and Tanjiro holding them. He felt Nezuko pet his head and chuckled. He laughed...!

"You'll never be lonely again. I promise I'll protect you, no matter what."

Zenitsu heard movement coming for them fast and immediately unsheathed his sword. Launching forward, he barely managed to block the flurry of attacks. He saw a black-haired man land by them.

"GIYU-SAN NO!"

It took Giyu a hot minute to remember Nezuko and Tanjiro, until Nezuko again took her protective stance, this time for Rui as well.

It hit him like a sack of brick, then Giyu frowned, "Why are you protecting him?"

Zenitsu didn't tremble. Or panic. Or cower. The weak, cowardly Zenitsu has left the chat, no one hurts his Rui. "He won't hurt anyone!"

Clearly, the man didn't believe that. Once again blocked all of Giyu's attacks smoothly. "My breath is lightning, and yours is water, this fight will not go the way you're hoping."

Giyu cringed in realization and at the blatant implication. Looking at Rui, the elder groaned at the cute little human eyes he saw.

"Tanjiro please stop converting demons everywhere you go."

Tanjiro laughed shyly, "I didn't do this one, it was all Zenitsu."

Zenitsu glared at Giyu with an overprotective aura, and he saw Rui adorably cling to Zenitsu. Clearly, this boy could've bodied him but chose not to fight. He saw no ingenuity or malice, it's like he was tamed. 

Giyu, as usual, felt a migraine come on from dealing with these kids. Sighing, the man pivoted. Immediately, he blocked the incoming attack from a beautiful butterfly girl. 

While they talked or calmly argued really, Zenitsu looked at Tanjiro and Nezuko and hugged them, "Thank you." They smiled and hugged him back tightly.

"Of course, Zenitsu! If you believe in him, so will I! You gave me the same grace and courtesy with Nezuko. How could I not? Plus, he smells sweet now."

Rui blushed and looked at Tanjiro, confused and flattered. "Long story, that has to be saved for another time!"

Giyu gave them a look, and the four took off into the forest while he fought Shinobu. They sprinted as fast as they could when another butterfly girl came out from the shadows like a ninja????

Zenitsu just ran faster with Rui and Nezuko, until he saw Tanjiro get sidelined and then his ass kicked. Zen snarled and gave Rui to Nezuko. He kicked the girl off his Tanjiro. She literally slammed into a tree and crumpled.

Tanjiro and Nezuko's jaws hit the ground, rightfully so.

Rui closed Nezuko's mouth and fixed her muzzle.

"Did...did you just hit a girl...?" Tanjiro genuinely couldn't process this. 

Zenitsu was far from in the mood and not playing games. "Damn right, let's go bitch."

Tanjiro would have never believed it if someone had told him this. Actually, fuck that, he STILL didn't believe it, and he was WATCHING it. His blonde drank "respect wamen" juice with every meal. And yet, still just smashed his heel into this girl's face.

Zenitsu and the girl went toe-to-toe, hand-to-hand, blade to blade. Didn't matter. They were scrapping. 

The other three just stared and thought the same thing, 'DAMN, SHE PISSED HIM OFF.' For once, he was consciously fucking someone up, and this girl was getting her ass whooped.

He was about to knock her out when a crow sounded overhead. It mentioned bringing Tanjiro, Zenitsu, Rui, and Nezuko back alive.

He gave the girl a glare that said, "Fine, you get to live...FOR NOW."

Getting off of her, he made a box for Rui out of the trees around them and used his haori to ensure no light got in.

Rui looked at Nezuko, who gestured for him to shrink. When he did, it took five minutes to get Zenitsu to stop snuggling him so they could get moving. Again can't blame Zenitsu. He's so cute!

Zenitsu was cranky and in a demonic ass mood when they got there. He got no sleep and used a lot of energy throughout the night. Physical and emotional energy. At this point, he made most demons look pacifistic by comparison.

He saw a bunch of colorful ass fruity-looking people. While he was confident most of them were friendly, he was far from in the mood for bullshit.

TLDR: Zenitsu was beyond pissed, they took Rui and Nezuko, AND they were bound.

'Fuckers...'

A few of them caught his eye, but one in particular. He had a bright smile, fiery hair, and his sound screamed determination, overall goodness, unyielding burning passion, searing love, and full-on purity. The man was a walking beam of sunshine and good vibes with the ability to snap your spine like a toothpick.

Zenitsu stared at the man in pure awe and amazement. The man looked at him, and his smile became more genuine, kind, and somehow BIGGER.

Unfortunately, he didn't get to say a word before a guy with scars, white hair, and wild eyes comes over with their respective boxes and, by extension, siblings. He didn't listen to a word he said. Zenitsu was focused on the boxes and heard Rui and Nezuko's fear. Their distress... Hahaha, he was gonna snap this fucker kneecaps... 

He eventually tuned into the man's rambles, "-I don't understand why you want to protect these things. One is a mass killer, and the other will become one. Killing them is the just thing to do." Oh, he was rambling bullshit. 

Zenitsu growled and scoffed in anger. "No, you'd be killing them out of revenge, not justice. Do NOT mix them up."

Multiple multicolored eyes snapped at him, with emotions ranging from shock to pride to curiosity to just plain impressed at his balls. 

"Justice would allow someone the opportunity for redemption, should they genuinely desire it. Should they be willing to truly desire to change. Everyone deserves a second chance. You simply desire to punish one child for being manipulated and turned into a monster, then left heartbroken. And the other for not even getting a choice or option for what she turned into. THAT IS NOT JUSTICE, THAT IS REVENGE AND CRUELTY, RESPECTIVELY." 

Lesson finished, the blonde snarled, his patience has finally run out, "PUT THEM DOWN NOW!"

All eyes were on him, but he ignored them.

Unsheathing his sword, the man gave him a challenging look, "Make me." He moved to stab the boxes, but he ended up stabbing his own arm. Everyone stared at the display in utter bewilderment.

Only Kyojuro managed to see it, merely because he was looking for it. The only one that noticed what happened. The blonde took the boxes in a flash. WITH. HIS. TEETH. It was a fluid movement. A bolt of lightning covered the distance. 

Nobody else realized until they heard the gentle thud of two boxes.

Golden eyes were practically molten as he stared at Sanemi in utter disgust. "This little piece of absolute scum....."

Zenitsu chuckled darkly, "No need to insult yourself so hard, buddy." His voice was dripping with venom.

Sanemi snapped and immediately attacked the blonde, who evaded the sword attacks and countered the physical ones using his legs. They were his literal strongest feature.

Zenitsu managed to get Sanemi to cut his ropes but in addition, his back. Ouch....

He didn't acknowledge the pain. At least not that pain. However, the kick to the stomach left him wheezing and retching (dry-heaving) on the ground in agony.

"Zeni!"

Through tears, Zenitsu saw Rui's box peeking open and saw Rui reach out. Immediately, the little one retracted his hand in pain at the burn from the sun.

"RUI, NO!"

Arms held his box shut before the child could say screw it and try again.

"LET ME OUT! ZENITSU!" The boy banged on the box.

"Your brother will be fine! He is strong! But he'll lose if he has to worry about your safety, young one!!!" It was the flaming man that held the box closed.

A whistle caught Zenitsu's attention, and he saw a younger boy with oversized sleeves, holding up his sword. He flipped over a charging Sanemi, narrowly missing a swing of his blade, and caught his sword as it was thrown to him. Throwing the sheath aside (a tall man with white hair caught that), he glared dangerously at his attacker.

The battle was fierce and fast. It was almost hard to keep up with. Nobody spoke. Nobody moved. There was only the clang of swords, and the faint crackle of lightning heard throughout the fight.

"THAT'S ENOUGH!" Using a little of his breath, he cut the man's sword at the handle.

The scarred man did not appreciate that. "I WILL KILL YOU!!!!!!!!"

"No, you will not."

Everyone snapped their heads to the new voice, and the pillars instantly bowed at the newcomer. Kyojuro gestured for Tanjiro and Zenitsu to do the same. They do hesitantly and reluctantly, again respectively.

"I want no more fighting." His voice was gentle and sweet. It made Zenitsu tired.

Zenitsu zoned out for the most part. Dizzy from the heavy exertion and pain in his ribs and really, the rest of his body. Especially his le-"You there, Zenitsu Agatsuma."

Snapping into focus, Zenitsu looked at the man, cautiously.

"How can you guarantee, that Rui will not cause harm? He's done it before."

"He almost burned to death in the sun trying to help me. He didn't break out of his box or lash out at the pretty, fiery man when he could have. Rui instead chose to trust him and take him at his word." He gestured to Kyojuro, who blushed a little at the compliment and laughed.

The white haired man with his sheath snickere at the box, "That box is honestly pathetically made. A harsh sneeze could make it fall apart." 

Bitch he had less than ten minutes, give him a break!

It was Kyojuro who spoke up, "I will test him! He may not attack Zenitsu because he trusts him, but what about someone he despises?"

Bringing Rui and Nezuko into the room behind the strange-looking man, he opened their boxes. Soon, he walked in with Sanemi and carefully cut the grey-haired man's arms before restraining him tightly so he couldn't attack.

Rui glared at him furiously and seemed to heavily debate killing him before ultimately turning to Zenitsu. His worry overpowered his anger. For now. 

"Are you ok, nii-san...?" Zenitsu smiled proudly and nodded.

Rui could tell he was lying, but let it go temporarily when he heard Nezuko. She was panting in hunger and salivating, but she stayed rooted to the spot.

Rui gently touches her shoulder, "Nezuko, come on, you're stronger than that, plus, I'm sure he tastes as rancid as his personality."

That snapped her out of it and got a laugh from her (and the pillars), and had Zenitsu rolling in laughter. She was finally able to turn away from Sanemi and clean herself up.

Kyojuro gives everyone a confident smile. "Rui successfully swallowed his reasonably demonic homicidal urges in favor of compassion and managed to ground Nezuko, but I don't believe she would've attacked either way!"

The master turned to the others, "Any other objections?"

"I DO-AH!!!!" Sanemi attempted to speak up...only to have his foot smashed by Kyojuro.

Everyone else wisely remained silent.

"Then it's decided, they will all join us as allies."

Kyojuro released Sanemi, who almost swung on him until he saw the rage in those usually gentle and kind eyes. Despite his smile, he was not having it. That was NOT a fight Sanemi wanted and certainly wasn't one he'd WIN.

He stormed off with a growl.

Zenitsu and Tanjiro ran to their respective demons and hugged them tightly. Zenitsu checked on Rui's hand, pleased to see he was already healed. 

Zappy locks fixed his gaze on the pretty fiery man, "Excuse me?"

He didn't seem to hear him.

"Excuse me!!!"

Looking down at him, he smiled and kneeled down. "Yes?!"

Ah, he is hard of hearing.

Zenitsu spoke up more, "Why did you help us?!"

Kyojuro thought before smiling, "Firstly, you're were ready to fight for your little brother's safety, something I relate to completely. Secondly, you remind me of myself! Your fire, passion, compassion, and fighting spirit! Your refusal to give up, no matter the obstacle! You were tied up and still ready to kick his ass! You desire to do what's right, rather than what's the rule! Your good heart will take you far. Let it lead you! I'm here for you, if you need it! Always! Both of you!"

The man grinned down at Rui, who quickly took a liking to the man. Once again, Sir Zappicus gazed at the man in wonder, before smiling and hugging him. It was gladly returned and man, he gave great hugs!

"Why did you protect me, then?" Kyojuro's gaze again flicked to the young demon by Zenitsu.

"You obviously mean a lot to Zenitsu, for him to risk death to protect you! And despite being a powerful demon, with perfectly good awareness that the sun is deadly to you, you still ignored that fact and was ready to charge out of that box and die for him. That is the most human thing anyone can do. Clearly, you were no threat, just someone who found what they needed to make their heart beat again."

Tears filled Rui's eyes, and he yelped as he, too, was pulled into the hug, which he shakily reciprocated. 

Soon Zenitsu was lying in the darkened infirmary after being treated. Rui was asleep in his arms, and he was gazing at the ceiling, processing his previous night and current day.

"Zenitsu...are you awake?"

The blonde turned to the gentle whisper, "Yes, what is it Tanjiro?"

The redhead sat up and looked at him, "I-I just wanted to say, you were amazing out there! Last night and this morning...you were incredible! I had no idea you could fight like that! Well I did...but you never showed that level of skill in you!"

Zenitsu blushed like a madman but resisted, his usual freakout for Rui's sake.

"I-I didn't know I could do that, but it felt good...You fought so hard, Tanjiro. You always fight so hard. I'm happy I could relieve some of the burdens from your shoulders."

Tanjiro's smile (somehow) managed to get softer and sweeter, "I knew Zenitsu was sweet and kind, so brave. Thank you for letting me see this side of him."

Zenitsu could've fainted on the spot.

The two demons continued to "sleep" and waited in anticipation. Both echoed the other's sentiments.

'Please kiss. Please kiss! PLEASE KISS! PLEASE KI-'

"W-Well, we should get some rest. We're rather messed up after all."

'DAMNIT!' Rui and Nezuko sulked in defeat at their brothers' idiocy before rolling over and finally going to sleep. They agreed on one thing, 'THE SHIP WILL SAIL!' 

Unaware of their siblings' thoughts, the blushing oblivious dimwits yawned and laid down to rest. After all, it WAS a very eventful day.

Chapter Text

Rui honestly still thought he was dreaming. He thought he'd wake up and either be with the faux family he created or dead with the family he lost.

He was wrong.

Instead, he woke up in a warm embrace and saw a sleeping blonde inches away. He knew it was real. He wanted to cry out in joy, and his emotional surge must've woken Zenitsu.

Pretty golden eyes fluttered open and glanced down at him.

As soon as he saw the tears and smile, he hugged the little boy, and all felt right.

"Good morning, Rui." The little boy grinned excitedly, "Good morning, Zeni-nii!"

Yeah, everything was just fine.

Rui and Zenitsu heard footsteps and looked toward the door. Rui saw teal hair and remembered the boy who was kind to them from yesterday. Zenitsu told him about it. The kid was holding some clothing, and Rui looked at them with interest.

"Apologies for the disturbance, but I have something for Rui."

Dark eyebrows vanished behind his pale hair as he stared at the boy. "M-Me?" Rui looked from the boy to Zenitsu, surprised.

Zenitsu heard no ill intentions from the boy, nor distrust, only kindness, and nodded in approval to Rui.

"I had it made for you. I hope it's sufficient." He set the fabrics in Rui's hands, and the demon's tears spilled over.

"My first...present...thank you!" He smiles softly at the boy, who returns a small smile of his own.

"I hope you find your place with us. I can't wait to know you, especially after the sass and courage you showed."

Rui looked at him curiously, "What's your name?"

The teal-eyed boy blinked at him owlishly, "Oh right, my name is Muichiro Tokito; I'm the Mist Hashira."

Holding out a hand, Rui's smile became more hopeful, "Wonderful to meet you, Muichiro." To Rui's surprise, a soft hand filled his, and they happily shook. 

With a tiny smile, he slipped out.

Almost immediately, Rui wanted to try on his new clothes, so the older boys helped him out. All of them heard giggling behind the makeshift changing curtain as Rui tried on his new clothes.

"I got it on!" The trio smiled and lifted the curtain.

At first, they thought Muichiro got the size wrong. The sleeves of the shirt and pants were too long, covering Rui's hands and feet; it also had a hood that covered his face. It was also made of a strange material.

Then it hit them, well Zenitsu and Rui.

It was to shield him from the sun.

Tanjiro moved Nezuko clear out of the way, and Zenitsu lifted the curtain a bit. Tanjiro held up the sleeve to it. Sure enough, no light pierced it. His whole body was protected. 

Nezuko noticed little clips in the hood and clipped them to parts of his hair. Rui twisted and shook his head. The hood never fell, and it didn't hurt him. It didn't tug on his hair, and it secured the hood.

The sleeves were still long enough that he could use his threads without danger. It was perfect for him.

It was still obviously a demon slayer uniform so others wouldn't hurt him. However, it had a unique design to represent Rui.

There were threads that spread and created an intricate web that went from red in the back to white in the front. He also had cute shoes.

It was the most Rui uniform that Zenitsu could imagine, and the look of pure joy on the young boy's face showed he agreed. "How do I look???" The two boys laughed, "You look amazing, Rui!"

Zenitsu hugged him, "Now you can come outside with us. You look perfect!" Rui couldn't wait to thank Muichiro. 

After eating and taking their medicine, the boys were outside, and Nezuko went back to sleep. Well, Zenitsu and Tanjiro were outside when they turned to their missing party. 

Rui stopped, staring at the sunlight apprehensively.

A hand slipped in his, and he turned to see a supportive Muichiro.

Muichiro gave him an encouraging nod. "You will be okay, I promise."

Rui didn't know why, but he trusted him. Slowly they took a step outside together. Both of their too-long sleeves swung along. His eyes were screwed shut in fear, and he braced for the worst...

Nothing.

He was actually okay. Soft blue eyes opened, and he looked around, amazed.

How long has it been since he got to see the daytime? His eyes stung a little, but he didn't mind at all. With a grin on his face, he ran forward. In doing so, he pulled Muichiro along, but surprisingly the boy didn't mind.

With a laugh, the teens followed them. The younger boy was ecstatic and cheered happily. He went to the little pond and grinned at his reflection. Everything was warm and beautiful. It was just as he imagined.

As he always dreamed.

Even alive, he never got to do this. The adorable demon couldn't be happier. He hugged Muichiro happily, "Thank you so much!!!!"

Muichiro blinked before hugging back gently, "Of course, Rui."

They heard footsteps and saw a scowling Sanemi, "What is it doing outside?"

A growl ripped through Zenitsu, but before he could say anything, Muichiro beat him to it. "What are you talking about?"

Pointing at Rui, Sanemi snarled, "THAT THING!"

Mui tilted his head, "The pond is always here." His voice was deceptively calm, dangerously calm.

"YOU KNOW I'M NOT TALKING ABOUT THE DAMN POND."

Teal eyes narrowed, "I know you aren't speaking about Rui, so you are speaking about the pond. Last I checked, Rui is a person, not an object. You will refrain from speaking to and about him disrespectfully."

Sanemi laughed in his face, "Or what small fry?"

Muichiro's foot lodged in his diaphragm, sending him to his knees before a swift kick to the balls from behind, courtesy of Zenitsu, sent him flying into a tree and crashing into the pond.

As Sanemi surfaced and stared at them surprised, Muichiro gave a cold look to him, "That's what." Taking a surprised Rui's hand, they walked away.

"You didn't have to do that!"

Muichiro looked at the boy, "I know."

Rui looked at him conflicted, "T-Then why did you? He's right... Why are you so nice to a mon-?"

A hand gently covered his mouth, "No one's allowed to insult you, not even you." The young hashira muffled his protest, "A monster wouldn't be trying to atone for what they've done. They wouldn't be genuinely trying to be better. A monster would've rightfully attacked Sanemi yesterday and today, but you didn't."

Rui looked at him slowly, not fully believing him.

"You're not a monster, Rui. You were tricked by an asshole and did horrible things out of desperation, but it's never too late to change. It's never too late to make up for what you've done. Avenge and honor the lives, you took."

Determination filled his soft blue eyes, and Rui gave a sharp nod.

"I don't always believe in giving chances, but I believe in calculated risks. I want to give you a chance. Prove me right."

Mui pulled his hand away, but Rui gently caught it between his own. "I will! Thank you, Muichiro! I will do my best!"

Muichiro pats his head and leaves with a wave, "I know you will."

Zenitsu heard that and simply smiled happily. He looked at Rui, who was staring at something, well, someone—a sulking Sanemi in the pond.

Rui ran off into the medical ward and then came back with a towel. He went to Sanemi slowly and gently held out his hand to him. He yanked it away when he was nearly met with a harsh swing.

Rui wasn't deterred and pulled the older man out by his collar. He shoved the towel in his hands and then ran back to the boys. Zenitsu gave Sanemi a dangerous look before leaving with Rui and Tanjiro, cooing over how sweet that was.

The man flinched from the look and stared contemplatively at the towel in his hands. He glanced back up at where the boys were and sighed, getting dry.

When Rui agreed to stay, he half expected to be kept in a dark room and neglected. A dumb thought considering Zenitsu wouldn't let that happen. However, he certainly didn't expect everyone to be so....kind?

Like they don't try to hurt him, they try talking to him and sharing stuff with him. Especially the butterfly girls, Mr. Rengoku, and Muichiro. It's strange, but he likes it.

He appreciates it deeply.

As the youngster was exploring the grounds, he saw a mini Kyojuro trying to train with a wooden sword.

He was...pretty bad.

Rui bit his lip, mentally debating it, then went over to him anyways. "H-Hi..."

The boy shrieked and dropped his sword. He turned to him and stared at him, startled, "H-Hello! I-I-I-"

Rui gave what he hoped was a comforting smile. The boy relaxed; it must've worked. "Need help?" Glancing at the sword on the ground.

Rui handed it to the boy, and the kid took it gratefully.

After thinking, he nodded, and Rui smiled. "Okay! Wait, first, what's your name?"

Oh, Rui forgot about that..."I'm Rui Ayaki-Agatsuma! Are you Mr. Rengoku's brother?"

Flaming hair bounced as the kid nodded. "He's the coolest! I want to be like him, but...I still struggle with the basics...Um, I'm Senjuro!"

"Nice to meet you, and don't worry. Everyone struggles, and everyone learns at different speeds. Let's find yours."

He helped the boy tighten and fix his stance. Rui slowly helped him perfect the basics. After a while of training, the pair moved in sync, and he truly was getting better.

A young man saw what was happening from afar and smiled happily. He trusted the boys to be alright and took his leave. Rui noticed him and was surprised but ecstatic.

'He trusted me...? Thank you, Mr. Kyojuro...I won't take your trust for granted!'

Senjuro had a confident, proud smile on his face for once. Rui cheered happily for him, and they high-fived. Suddenly a frown settled on Rui's features as a lousy feeling curled in his gut. 

"SENJURO!!!!! WHAT ARE YOU DOING?!"

Said boy immediately whimpered and hid behind an unimpressed Rui. Welp that answered that...he sensed a threat.

A much older, messy, downgraded Kyojuro came out. He took one look at Rui and snarled, "WHY ARE YOU WITH A DEMON?! GET AWAY FROM HIM!"

Senjuro's eyes widened as he looked at Rui and then at his father. "N-No..."

The Rui and the man's eyes widened in shock, "What did you just say, brat...?"

Rui glared, "Don't fucking call him that."

The man laughed, "A creature like you doesn't even deserve to speak. Now leave, or I'll make you."

Rui had no fear. His priority was to protect Senjuro. His demonic features overtook his appearance. "Come make me, bitch."

Old Man Rengoku drew his sword and charged at them. Rui used his threads to move Senjuro safely out of the way as he blocked the onslaught of attacks.

Seeing his friend being attacked was too much for poor Senjuro. He began to cry and scream, "KYOJURO!!!!!!!!!" The scream rang far. Reaching the ears of three demon slayers that sprung into action.

The youngest got there first, managing to kick the man over his little brother hard as hell. Old Rengoku flew a little away from them, and the much younger slayer took a protective stance in front of Rui. "BACK OFF, MY LITTLE BROTHER!"

Unfazed, the man swung, and Zenitsu countered.

Rui got to his feet, "This is my fight! I've got it!"

Zenitsu turned to him, frowning, "You no longer have to rely on only yourself! Get to your friend!"

Realization replaced his anger, and Rui blinked, shoulders sagging, "You're right...." Hearing crying, he looked up and saw a mortified Senjuro.

Rui jumped up to the boy, who hugged him tightly. "YOU! GET BACK HERE AND DIE!!!!" Rui paled as the man violently threw Zenitsu to the side before throwing his sword at them. Rui grabbed Senjuro and jumped out of the way.

Immediately, Rui ran with the boy in his arms until he ended up tripping on the unfamiliar rocky ass path. 'UGH!!!!!!!'

He was frustrated and angry.

"Nowhere to run now, kid. Hand me the brat, and I might give you a merciful death." He again used his threads to move Senjuro out of the way and turned to the man seething.

Well, he tried to be nice. 

"You. Don't. Scare. ME!!!!!!!!!!!!" Summoning his threads, he fought. 

As tempting as it was, Rui tried not to hurt him in both rounds. Well, at least not fatally.

He tried to tire him out and incapacitate him while sneaking in occasional licks. It was absolutely annoying. However, the Rengoku brothers probably want their sorry excuse of a father in one piece.

He was finally about to incapacitate him when he was violently kicked away. He saw the snake man and Sanemi there.

'I just can't get a break.'

"Attacking a civilian? So much for not being a monster."

Rui was so over his shit and glared, "YOU DON'T EVEN HAVE THE FULL STORY OR A SMIDGE OF CONTEXT!"

A mocking laugh was his answer, and he deadpanned at the man. He should've let him catch a cold in the pond...

"What valid reason could you possibly have for attacking a civilian and former demon slayer!?"

"He-"

Sanemi scoffed, "Save your breath. It's over."

A blur of gold skids in front of Rui, "Unless you want round three of me kicking your ass, FUCK OFF MY BROTHER ALREADY."

Sanemi rolled his eyes, "This time, he's in the wrong. You can't save him."

Two flashes of orange, red, dark blue, and gold landed by the brothers, "WE'LL BE THE FLAMBOYANTLY FABULOUS JUDGES OF THAT!"

A grinning flashy white-haired man and the shining sun known as Kyojuro stood before them.

"That thing attacked your father, Kyojuro! And probably killed your brother!"

Kyojuro's smile left for the first time, and a dark glare settled.

Everyone shuddered.

"Watch the bullshit that leaves your mouth. Rui did not and would never hurt Senjuro. And I'm certain he didn't start this fight."

Iguro took over before things could escalate, "How are you certain?"

Kyojuro took a step forward, and they took two back, "When I left, he and Senjuro were friends, and he was even teaching Senjuro to fight—doing a pretty damn good job as well. My dad is a very crude and volatile drunk. To be blunt, an asshole. 

Despite the two fighting, there aren't any severe injuries on my father. If Rui were truly trying, he'd be seriously injured and possibly dead. And finally, Zenitsu's head is bleeding from hitting something blunt, presumably a tree or a rock."

Sanemi was seething, "FINE THEN DETECTIVE, WHERE'S YOUR BROTHER THEN?!"

"I'm here!!!"

The boy was gently brought down in a thread-made little net. As soon as he was set down, he ran to Rui to check him over.

"Yeah, he's totally a threat to Senjuro." Mr. Fabulous smirked at Iguro and Sanemi. "Suck it up, man, you're not getting rid of the kid, and he's a valuable member of the corp. Plus, have you seen this kid? He screams, "Flamboyant potential." Now help me get this mess home."

Grumbling, Sanemi, Kyojuro, and Tengen brought Mr. Rengoku home. Iguro looked at Rui and bowed in apology, who gave him a sweet smile in acceptance. The crinkle of Iguro's eyes gave away his own smile as he left. 

Zenitsu grumbled, then froze. He heard loud footsteps.

Turning, he saw Mr. Rengoku descending on Rui, similar to what Zenitsu did before. Only this time, he doubts it'll change to a hug...

Suddenly, Rui was shoved to the side, and they heard the clash of swords.

Snapping his head up, the arachnid demon saw Senjuro holding a spare sword with a determined frown.

"MOVE, SENJURO!" A growl ripped through the boy, and he knocked his father back the best he could.

"NO! HE'S DONE MORE FOR ME IN ONE DAY THAN YOU HAVE IN FAR TOO LONG! I CONSIDER YOU A MONSTER MORE THAN I EVER WILL HIM! HE'S MY FRIEND!"

His father narrowed his eyes, "Fine." His father reeled back and, this time clashed with a different sword.

Zenitsu.

"How pathetic."

The two younger boys took on the man. Well, Senjuro did his best with his basic knowledge. 

Rui's patience ran out.

He leaped over the man and grabbed his shoulders with his threads before slamming him over him and to the ground. It knocked the wind out of the man leaving the man dazed.

However, it was Senjuro, who finally put him out using the hilt of the borrowed sword.

The two humans panted tiredly. Hearing more footsteps, Rui growled and whirled on the person, but it was only Kyojuro, Tengen, Muichiro, and Shinobu running over.

He finally slumps to the ground and breathes. 

"Is everyone alright?" Shinobu was checking them all over.

"How did he get out of your hold?!" Zenitsu was looking at Tengen, confused and pissed.

"He didn't! Sanemi let him go and held me back and Kyo so he could go for Rui. We couldn't get to him until we handled Sanemi!"

Zenitsu made sure he was being truthful before huffing.

Rui went to Kyojuro, "Your brother protected me."

Kyojuro looked at him confused and kneeled, "Senjuro can't fight." Rui shook his head.

"He can! He did amazing!"

Zenitsu made a noise of confirmation while Senjuro slowly returned the extra sword to him. Kyojuro stared in shock, then smiled in pride. He hugged a now shocked, Senjuro.

"Great job, Senjuro!"

Senjuro snapped out of it and hugged back happily, "Friends protect each other! And he worked so hard to protect me earlier. How could I not?"

Kyojuro's never seen this much confidence in Senjuro before, and he was so happy for him. He gave Rui a look of thanks.

Rui smiled happily and nodded. "Senjuro...can I see you again?"

The youngest Rengoku turned to him immediately, "Anytime!" Bright grins bloomed on their faces, and the boys warmly hugged. 

All too soon, the little demon finally parted, with Zenitsu, Muichiro, Shinobu, and Tengen following. Grabbing ahold of Zenitsu's hand, he stopped him.

"Thank you for coming, Zenitsu." Zappy best boi looked at him protectively, "Hey, I was serious! I'll always be there when you need me! You're my little brother, and I take that seriously. You're mine to care for, love, and protect."

Shinobu smiled a rare genuine smile, listening to the two, and Tengen tried to look like he didn't care (he failed.) Rui simply hugged the boy's arm as they continued their walk.

"And I'll always protect you, Zeni-nii." A soft smile spread across Zenitsu's face, "I know you will." There wasn't a hint of doubt in his voice.

After that day, things changed a bit. Everyone (except Sanemi, of course) was much kinder to him. He wasn't genuinely seen as a threat anymore. He was even invited to dinner, and though he didn't need to eat, he chose to.

He forgot how tasty food was. He missed it without realizing it. It became a simple pleasure he indulged in. 

However, this new acceptance also meant he started training again. He couldn't become strong in the traditional demon way, so he took a more human approach.

Exercise, training his powers, expanding their limits, and sleeping more but not as much as Nezuko. 

Or he'd be on the sidelines cheering Tanjiro, Zenitsu, and Inosuke on.

He was becoming the demon, Master desired him to become, just not with his cruel methods. Master. He hadn't thought about the demon in a bit. After all, the man had become a faux father to him, but now...?

He wasn't sure how to feel...

Master let him get away with so much compared to other demons and genuinely seemed to care. At least to him... His previous family was technically against the rules.

After all, Muzan never liked demons banding together, but he allowed Rui to do it...

He wonders how the man would react to his choice. He knows the man would be enraged and wouldn't handle the betrayal anything short of horrifically. But a small part of him really wanted to believe that maybe...he'd be happy for him.

A family is all he wanted, and Muzan knew that. 

Being with others is what he craved, and he finally got it, just in an unexpected way.

If Zenitsu never came along, he'd either be dead or still with his faux family. He's happy now.

Truly happy, and it was all thanks to Zenitsu. 

One night, he was sitting by the pond with Zenitsu and Nezuko. They had just finished training for the night and were resting. The water was beautiful, and the night made everything ethereal.

They all looked over, having heard soft footsteps, and saw Mr. Ubuyashiki coming over.

They all gave a respectful bow. "M-Mr. Ubuyashiki, hello!" Nezuko made a sweet noise in greeting. Rui simply hummed. The man laughed softly, "Relax, Zenitsu, no need to be so tense. I merely wanted to check on you all."

That made them all relax. "Would you like to join us?"

The man tilted his head at the little demon's question before nodding. The man sat by the lake but misjudged the angle, and Rui caught the man with his threads before he could fall into the water. He gently placed him on the grass by the pond.

"Thank you, Rui. I appreciate that a lot."

Rui giggled shyly, "No problem, I didn't want you hurt or all wet."

The man smiled wider but no less kind. "You truly are sweet. Are you enjoying your time here? You feel safe, yes?"

That was an interesting question. "Yes, I am happy here. Almost everyone is very kind, and I'm learning many new things!"

Which is true. Most of the Hashira have taken to teaching the boy different skills and lessons that he was enjoying.

He always did love learning; he just couldn't explore as he craved.

"I've heard the hashira gushing about you all. They really enjoy the company."

That made them very happy. "However, I will admit I am curious. Do you miss anyone from your old life?"

That question made Rui's eyebrows vanish into his hair in surprise, and Zenitsu's eyes ballooned.

"I-I um..."

The man pats his head, "It's not a test. Relax...you won't be executed for having friends. You were with them for a while. It'd be more surprising if you didn't have anyone you missed."

That made Rui relax a bit and actually think about it, but he knew his answer. "Just two. One's name was Kokushibo; he's an upper moon. He spoiled me a little and was very kind when in a good mood. U-Um...and the other is....well...."

Kagaya nodded in understanding, "Muzan."

Rui nodded, while Nezuko scrunched her nose in distaste. Looking down guilty, he went quiet. Nezuko cooed and patted his head.

"So he was nice to you?"

"Yeah, very. He was the closest I had to a father since I...made my mistake..."

Nezuko gave him a hug, and he calmed a little.

"Well, I'm glad you weren't very lonely. I hope you never feel that again."

Rui looked around, seeing the Hashira, Inosuke, and Tanjiro training or relaxing. Overall a very peaceful atmosphere.

"I don't think I will."

With a beautiful smile on his face, he gently held the older man's hand. The hold was gently returned. Zenitsu and Nezuko gently hugged him. Everything felt right, but unfortunately, peace never seems to last long. 

It was a little while later, on a bright day, that Rui was training with everyone. He was helping the boys with their grace, flexibility, reflexes, and core strength. Using his threads, he created one hell of an obstacle course. 

He made sure to keep his eye on them, so they didn't lose a limb or worse...

Inosuke did the best as expected since he had the most grace and bodily control, able to contort and hold his body at interesting angles. As well as a powerful sense of his surroundings and movement within those surroundings. He could sense even the most hidden thread and avoid it. He was utterly flawless. 

The second best was Zenitsu having lightning-quick reflexes, impeccable speed, and reaction time. While he wasn't the best with upper body strength, it never slowed him down. His powerful core, lower body strength, and hearing made up for it. Besides, this forced him to improve that strength. He was amazing!

Tanjiro wasn't bad by any sense of the imagination, but he wasn't the best out of them. He was the second most balanced, strength-wise, the first being Inosuke. But nothing in his body made him exceptional besides his high pain tolerance and drive. But all of them have that; they couldn't be here without it.

Yet, he still made it through impressively, and he was merely more determined to improve.

The training was going well until Muichiro joined, and his focus went to Jupiter. Only barely managing to keep them from maiming themselves as Shinobu instructed them to take a break. 

Shinobu gave him a smile that screamed trouble. She went to him, and he debated running. "Rui~! Honey, have you taken a liking to Muichiro?"

"Only a bit...y'know...he's cool..." His face looked like a tomato, and her smile became wider. "Oh really? I see." She pats him and left to talk to the other three. 

As they all rested, he watched Muichiro and Shinobu spar. To say Rui's jaw dropped was an understatement as he watched them glide across the field. Not only was he eternally grateful not to go against either of them, but man, was he stunned by Muichiro. 

Shinobu's smirk turned into a near-shit-eating grin when she glanced at him.

Yeah, he was busted...

He knew his face was probably lovestruck, and he could feel the blush on his cheeks, but he couldn't help it. Muichiro was so cool! 

After their spar, Muichiro gave him a wave, and Rui shyly waved back, looking away flustered. He missed Mui's frown and Zenitsu's face turning deadly. 

Soon the three were given new instructions, so Zenitsu's bloodlust had to take a pause. 

"And you are coming with me~!" Sulking, he followed Shinobu and looked up in time to find a sparkling Mitsuri there with lunch prepared. 

"Rui~!" She scooped him into a hug which was immediately returned. "Hi, Mitsuri!"

Setting him next to her, she smiled brightly, "Hehe! Shinobu said you needed some help?" He immediately glared at her, but she merely giggled at his expense, "Seems little Rui here was bit by the lovebug~."

Mitsuri immediately squealed and gushed out question after question making his head spin. "WHO IS IT?!"

"No one! I-I mean...um..." Looking at Shinobu, she gave him a nod, and he sighed, "...M-Muichiro..."

"OH MY STARS, YOU'D BE SO CUTEEEEEEEE! Oh, and he adores you, Rui! Why wouldn't you tell him???" He wished he could be so carefree, "Sweetie, I'm a demon with blood on my hands..." 

"LOVE SURPASSES ALL WORRIES! He's cared about you despite all of this and went above and beyond to help you! Even making your clothes comfortable, stylish, and functional! Trust in yourself and your heart! See what he sees!"

He looked at her with stars in his eyes and sniffled. "Yes, ma'am..." 

She smiled proudly at him and huffed, "Good! Now let's eat!" Laughing, the three had a nice lunch as her words danced in his mind. 

Rui tried to confess...he really fucking tried...

IT JUST WAS NOT GOING WELL! 

He was always shy! Always tongue-tied! Even with Nezuko and Senjuro's encouragement, he just couldn't fucking do it. 

But now practiced all morning to tell him, and he was more than ready.

"M-Muichiro!!!!" Said slayer stopping from where he was walking with Tengen and Mitsuri, "Hello Rui, is something wrong?"

"I-I NEED TO TELL YOU SOMETHING!" Mitsuri silently jumped in excitement and gave him thumbs up in encouragement. Tengen was grinning his ass off, watching until he heard something that took his attention.

"I-I really li-!" 

"RUI! COME ON, COME ON, COME ON! WE HAVE A MISSION!" Zenitsu grabbed him as he dashed past.

Rui could only blink in shock. 

Then shock turned into rage, and everyone around was well aware, "GOD MOTHERFUCKING DAMNIT ZENITSU!!!!!!!!!!!!!!"