You were captured when you were wandering around the Infinite Castle. you wake up after a while, but you were tied up inside a room where Akaza, douma, kokushibo and muzan were also standing there looking at you

Douma: How cute~!

Akaza: What We gonna do whit that weak..."thing"?

kokushibo: ...

Muzan: "I hope they didn't capture a useless human... ughh...