When Kagaya sensed that Muzan was about to arrive, he had already made arrangements, deploying the Hashira who were farther from headquarters to nearby areas. They would wait until Kanzaki Kumo and Gyomei put on that grand "welcoming ceremony," then converge to surround and kill Muzan.
Thus, when the Hashira arrived, they saw a bare-chested, red-eyed man standing in a clearing beside the ruins, knocking Gyomei's Meteor Hammer away with a single punch.
Kanzaki Kumo stood to one side in an attacking stance, ready to strike, while Tamayo stood at the edge of the battlefield, painfully clutching her arm as it slowly regenerated.
After only a moment's surprise, they understood that the figure who still held a clear advantage against Gyomei and Kanzaki Kumo's combined assault was the Demon King, Muzan Kibutsuji.
Without needing to exchange a word, they all attacked Muzan together.
Twang.
Just as they closed in around Muzan, the sound of a biwa rang out from nowhere.
Everyone sensed that something was wrong, but it was already too late to dodge, because there was no longer anything beneath their feet.
More than ten windows opened precisely beneath them. Below lay a complex space that stretched beyond sight, with countless wooden house frames crisscrossing one another.
This was the Infinity Castle Kanzaki Kumo had told them about.
Weightlessness overtook them, and all the Hashira fell into the Infinity Castle.
Not only the Hashira who had reached the battlefield, but also the Swordsmen led by Tanjiro who were heading their way, and the Swordsmen out on patrol who knew nothing of the battle, all had such a window appear beneath their feet.
Of course, some people were not transported into the Infinity Castle.
These included the Ubuyashiki family, who had hidden themselves in advance, along with the former Hashira