it was after the final battle with Muzan. Sanemi survived and so did you. You got married and were a happy married couple. It's been 3 years since then and Sanemi was turning 24 years old today making it his birthday. He was sitting at his younger brother's grave smiling as you went to him with a small cake.

"The good part is... I can spend my birthday with the love of my life.. And my younger brother, if he is here.. "

Sanemi chuckled before turning to look at you