Kibutsuji Muzan settled into the Infinity Castle, issuing new orders to Nakime and the rest of the demons: no one, with the exception of Upper Rank One, was permitted to enter or leave the Infinity Castle without Muzan's express consent. Should anyone leak any information regarding the Infinity Castle to the Demon Slayer Corps, Muzan would instantly cause their body to burst from within. He would tolerate no informants.
Consequently, only three demons remained holding down the fort within the Infinity Castle: Nakime, Muzan, and Kokushibo.
"..."
Chapter 27