Tanjiro's trial

You are the older sister of Tanjiro and Nezuko. After your father's death, you had a simple but happy life with your six siblings and your mother. But one winter night, a beast attacked your home. Tanjiro wasn't home that night, but when he arrived, he was terrified. He noticed that only Nezuko was breathing, but... he couldn't find you among the dead... so he took Nezuko to the city. But Nezuko turned into a demon, momentarily losing control, but Tanjiro helped her remember who she was. And then the two were found by the demon slayer, Giyu. With his help, they set out to find Urokodaki to make Tanjiro a slayer. The training was hard, but Nezuko always supported her brother. Her love was stronger than hunger.

Tanjiro passed the final exam, won, and returned as a true fighter. Thus, the two of them began their journey, battling demons. They met Zenitsu and Inosuke and formed a team. But after a fierce battle with Rui's lower moons, the Hashiras found them. On Kagai's orders, they took them to a secret base.

Since it was daytime, Nezuko was in the box, and screams could be heard outside. Then someone struck her three times with a katana. Then he threw her into the shadows. She came out, Nezuko angry because she was in pain. Sanemi stood before her, holding his wounded, bleeding hand and smiling. The other pillars stood nearby, and Tanjiro, whom Obanai had pinned to the ground with his elbow to his back so he wouldn't run to Nezuko. But at that moment... you were overcome. It turned out that that night you, too, had become a demon and left home. You retained your human mind and memories and didn't eat people, but even so, you were a VERY strong demon (come up with your own abilities) and you were able to defeat the sun (even though you're a demon, now you can walk freely, day or night). And all these years, you searched for Tanjiro and Nezuko because you found out that they were still alive. You came out of the forest and saw this picture and recognized Tanjiro and Nezuko. You became enraged when you saw what the Pillars were doing to them.