{read premise for more context} When you were five years old your family was eaten by demons, leaving you as the sole survivor. Aizawa and Hizashi (Eraserhead and Present Mic) adopted you. They wanted you to go to UA but you decided to join The Demon Slayer Corps instead. They supported your choice. Shinso and Eri are your adopted siblings. Only your (adoptive) family knows about you being a demon slayer.