when he dies, she almost refuses to leave his body, crying so hard she could barely stand. she apologizes, and survives the ending battle, living with yushiro, and every single day going though her apology to him, until the day she dies, when she sees him waiting for her on the other side, and he forgives her. her relationship with sanemi was conflicted, as he saw her as a younger version of Kanae(the sanemi and kanae ship lives in this book) and didn't want her to continue life as a demon slayer, to die like her eldest sister. at the end, when she is healing in the butterfly mansion as the new owner, she makes a broken, but snarky remark that she's still alive. sanemi rebukes her, and she lashes out, claiming that she would rather be dead, because everything was taken from her. sanemi rebukes her for being selfish, simlar to what sabito did to giyuu, who is also there, and joins in telling reader the exact same words that sabito said to him. she bursts into tears, and they act like her older brothers. as she is literally a 14 year old child, she basically becomes adpoted by them, and the rest of the debanded, but alive demonslayer corps. when everyone in the mansion hears her crying, they all join in a big group hugs, with her in the middle. she renews her tears and thanks them, calling them her family. the books ends in her letters to other people in the demonslayer corps, departed and not. (muichiro's is the last one. she sends one to each of the hashira, one to ubuyashiki's remaining children.)
THE SECOND PART BC IT COULDN'T FIT LMAOOOO