The Hashira's were always told stories of a certain Hashira, the Eclipse Hashira. They had no idea that she was real... (Y/N is the chosen mother of the Kamaboko Squad, Tanjiro and Nezuko think of y/n as their mother. Inosuke only listens to y/n, Zenitsu and Genya find the feeling of safety with y/n, and Kanao doesn't feel stressed around y/n.) Y/N is Master Ubuyashiki's sister, she isn't known to the Hashira's only the Kamaboko Squad. One day when the Hashira's were walking together, they found y/n, they believed she was a demon because of the star constellation mark around her white eye. (The white eyeis a blind eye, the other eye is a shade of light purple, the mark is a slayer mark, even if it looks like a demon mark). They had no idea that y/n is Master Ubuyashiki's sister, and that she is the 'mother' of the Kamaboko Squad. Y/N is much like Yurchi, y/n is one of the few people Muzan is scared of. Y/N is the Eclipse Hashira, Eclipse breathing is the hardest breathing and the strongest. She takes secret missions and was just sitting when attacked. The Hashira's ended up, not killing but painful knocking y/n out, (because y/n wasn't going to fight back), and bringing her back to the headquarters for an order from Ubuyashiki for what to do with her. ...they had no idea they hurt and knocked out the strongest Hashira, an Ubuyashiki family member, the Ubuyashiki children's aunt, the Kamaboko Squad's mother, the reason Kagaya Ubuyashiki is still alive, mistaken her as a demon, and tried to kill her. They would soon realize what they did when Kagaya Ubuyashiki, Amane Ubuyashiki, and the Ubuyashiki children find out.