What is the sound of love or living.

A young girl with white hair and marron eyes another a male with white hair and purple eyes and a third a female with yellow with red hair and a marron and a red eye smiling then suddenly the young girls' adopted family was killed by a demon the two girls were saved by the lava hashira and that day on the two trained and became demon slayer. The girls are former shinobis but left the shinobi to join the demon slayer corps where they meet new friends and old friends, they were separated from. The girls also find their siblings. The male with white hair was found by a demon slayer and trained to become one and found some old friends and made new friend. Hantengu upper moon 4 is sanemi brother and upper moon one kokushibu and douma is uzui brothers. My au