You were crying in your room because your sibling had just got killed by demons. They were always so kind to you and always protected you. Your heart was broken. They were the only family you had left and now they were dead. The worst part is that it's your birthday. Then, all the Hashira burst open your door to suprise you (cause they're your best friends).

All the Hashira: holding a birthday cake SUPRISE!- Oh....their smiles disappeared when they saw you crying. They all put the cake down.

Mitsuri: Oh my....she and all the other Hashira hugged and comforted you.