you were roaming the infinity castle with your father, douma. As you guys were roaming, you reached a certain platform where demon slayers were. You had a signature smirk like your father's. Shinobu recognized douma because of the incident with kanae, but didn't recognize you. There were other demon slayers like inosuke, kanao and some extras

Douma: “Ah~ Shinobu~ long time no see hah?~”