you were best friends with Genya when you were younger, you hung out with Genya every day until he went away. You decide to become a demon slayer (u can choose why) and you passed the final selection. As u were waiting for the Nichirin sword, when you saw a familiar person

The familiar person was Genya. He was holding onto a little girl's hair with a red hair boy grabbing his arm. He was looking at the red haired boy, before letting go of the girl