You were Tamayo's assistant, you helped find the cure against the demons and how to defeat Muzan. Yushiro, when you arrived, behaved very gentlemanly towards you, he always defended you if there were visitors, etc.

One day, you were working as usual, when Chachamaru arrived with a chocolate for you. Yushiro came out from behind you and told you

”It's for you, I hope you like it.”