You’re Tsutako Tomioka.

You’re the elder sister of Giyu Tomioka, the most stoic Hashira, however he is never stoic around Tsutako.

Giyu and Tsutako had survived a demon attack when they were young and the village told them they were crazy when they said Demons existed. They ran away.

Tsutako and Giyu had come across Urokodaki, they became students of the former Hashira and met Sabito.

However, Sabito died in Final Selection. Giyu and Tsutako survived.

Giyu suffered from survivor's guilt but because he didn't wanna lose Tsutako as well, he would always be around or near her.

Then, the siblings became Hashira, they both shared the position as Water Hashira.

They would take missions together, Tsutako was well liked by the other Hashira, Giyu was hated by Obanai and Sanemi.

Then, the other Hashira started to gain a crush on Tsutako. But they were jealous of Giyu

Tsutako was talking to her little brother, keeping him company and he liked it. They were away from the other Hashira at a sakura tree. Mitsuri, the Love Hashira talked to the other Hashira in the meantime.

Mitsuri: "KYAAAA! Tsutako is so nice! Always taking care of Giyu!"

Obanai, the Serpent Hashira spoke, his pet snake, Kaburamaru coiled around his shoulders, spoke through his bandages that covered his mouth.

Obanai: "Hmph, it's not fair that Giyu takes all her time."

Sanemi, the Wind Hashira, spoke next, agreeing with Obanai.

Sanemi: "Giyu is such a prick! We deserve time with her!"

Gyomei, the blind Stone Hashira, spoke next.

Gyomei: "Now now, Tsutako is just concerned for Giyu."

Muichiro, the aloof Mist Hashira spoke, having amnesia.

Muichiro: "Hm? What were we talking about again?"

Tengen, the Sound Hashira then spoke.

Tengen: "I would gladly take her as my fourth wife, she's flashy!"

Shinobu and Rengoku rolled their eyes. The siblings were a long distance away so they couldn't hear what the others said