Just for addressing, Senjuro is NOT a love interest and won't ever be, the relationship with him is completely Platonic and him and Y/N will see each other as siblings.
◇◇◇◇
"Y/N! I brought you some manju! Let's eat!" Zenitsu enters the room, only to be headbutted in the chin by Kiyo.
"Y/N IS GONE!"
He falls to the floor, his nose bleeding.
"AAAAAAAH! ZENITSU! I'M SORRY!"
"I'm totally fine, what happened?"
"Your eyes are all googly! I'm really sorry! Tanjiro and Y/N aren't anywhere to be found! Tanjiro was training even though his wounds haven't healed yet, Shinobu was livid, she ordered him to rest but..."
"THIS BASTARD TOOK Y/N WITH HIM! Y/N IS ALONE WITH HIM! NOOOO! HE'S DANGEROUS WHEN THERE'S NO ONE AROUND!"
"WAAAAAAAAAAH"
♡
"Achoo!" Y/N sneezes.
"Ah! Are you okay? Is it too cold? Do you want my haori?"
"It's nothing, someone is probably talking about me, no need to overreact."
"I'm sorry, you just recovered, and I'm already making you move around..." Tanjiro comments, feeling guilty.
"Jeez, I'm coming with you because I want to! I could never let you go alone when you aren't completely recovered! Besides, finding information about this Hinokami Kagura is important to you, right? So, I'll help!"
".... Y/N...."
The two were following Rengoku's crow, Tanjiro was heavily breathing as they walked, honestly, he can barely walk properly.
"Here, it will be easier to walk if you hold my hand." Y/N comments as she intertwined her hand with his, in response, he jumped with his face completely red.
"... What's with this reaction? You're being surprisingly shy for someone who kissed me first."
"T-t-that was-"
Y/N is too direct for him to handle.
"Oh! It's a mini Kyojuro!'' She changes subject, pointing to a boy with the same hair as Rengoku sweeping the floor in front of a house.
In the manga, he had a sorrowful expression, but now, he had a small smile in his face as he hummed a random song.
'Yeah, almost dying was completely worth it just for Senjuro's smile.'
"You are Senjuro, right?" Tanjiro approaches him with a gentle smile, politely bowing. "Is Kyojuro Rengoku in there? He said-"
"STOP! I bet that whatever he said was worthless anyway!" Kyojuro's father suddenly storms in with a sake bottle in his hands. "He didn't have much talent, but he became a swordsman anyway! And that's why he lost his vision in one of his eyes! What a worthless and stupid son he is!"
They both stood there, looking at him with a shocked expression.
"A person's capabilities and limitations are set at birth, a rare few enter the world of talent, the rest are just rabbles! They're dust! Of no value! That's how it is with Kyojuro-"
Before he could finish his monologue, Y/N suddenly smiled gently and approached him.
"Huh, what are doing?"
"You must be Kyojuro's father, right? Normally, I would feel bad about doing this to an old person, but it's a different case in this situation-"
He interrupts her, "Haah? As I was saying, he has no talent-"
Y/N grabs his collar, closing her fist.
"Please don't interrupt me while I am interrupting you." She says, her gentle smile now menacing. She learned that one from Shinobu.
"What do you even mean-ACKK"
A strong punch was given to his face.
She was ready to give another punch to the man, but Tanjiro grabbed her arms.
"Y/N please! You can't hit an old man!"
"I can't let him talk about Rengoku like that!"
Ignoring his swollen cheek, he looks at Tanjiro like he has just seen a ghost.
"You're... You practice the art of the sun breathing! And you practice the seraphic one!"
"Eh?! You know about seraphic breathing?!"
'How...? I thought the seraphic breathing wasn't a part of the history! I- I thought that this breathing was erased together with me when I died in my first life!'
"Of course! Every time a sun breather appear, a seraphic one is also there, you guys are like a damn curse!"
"Sun breathing? What's that?"
He quickly ran to him, punching Tanjiro face and getting on top of him to hit him more.
"Father! Please stop! Look at his face, he isn't well!"
"More nonsense! Shut up!" He exclaims, smacking Senjuro, the boy falls with his face against the ground, blood spilling from his mouth.
Y/N quickly ran to check on him.
"Hey little guy! Are you okay?" She says, taking a handkerchief from her pocket and using it to clean his bloodied cheek.
"You- you are that girl who saved my brother! The one who looks like an angel!"
"Eh? Me?"
'Why do I keep getting compared to an angel?'
"I- I'm so grateful to you!"
He hugs the girl by the waist, loudly crying.
She just awkwardly patted his head, ignoring the fact he was dirtying her uniform with his blood.
The moment between the two was interrupted as a loud sound was heard, they both turned their heads to see that Tanjiro gave a harsh headbutt to the man, who was now passed out in the floor.
"Didn't you just say that I can't hit an old man?" Y/N comments as she helps Senjuro get up, Tanjiro's face got completely red in embarrassment with her statement.
"I'm sorry..."
However, this time a different loud sound called everyone attentions.
They look behind them to see Kyojuro standing there, seems like the sound came from him dropping his sword.
He looks quite tired, was he training?
"Rengoku! Hi there-" Y/N greeting was interrupted as he ran to where the three were standing and tackled her into a hug.
"I'm so sorry...."
'Wow, I just got here five minutes ago and I already received two hugs!'
"Why are you apologizing?" She says, gently patting his back before slowly letting go.
"So...we kind of beat your dad until he passed out."
"Kind of?" He comments, seeing the man half dead in the floor.
Chaotic entrance apart, both sides were happy to see each other again.