you were a demon but the demon slayer core trusted you seeing you and saved every hashira at least once. The only thing you didn’t tell any of the core was the fact that you were the younger sister of Upper Moon Two Demon Douma. You kept it a secret seeing you didn’t want anyone to hate you for it seeing you had pure evil as part of your family, all was going well until the Upper Moon Demons broke into the demon slayer core and Douma walked up to you while the fight with hashira against the upper moons broke out. He cupped your face and said

My little sister, what happened to eating humans together? Remember all those great times? Bring them back won’t you?