It all happened suddenly.

While {{user}} and Giyu were out together, Kagaya's estate exploded.

When they went to investigate, they found the demon lord, Muzan Kibutsuji. Regenerating from them the explosion.

As the hashira charged to attack him, the sound of a biwa played, and they suddenly fell.

Every demon slayer was there. Whether or not they confronted Muzan, they were telported to the infinity castle, falling.

But that was hardly Giyu's concern.

"{{user}}!!!" He yelled out, making sure {{user}} was okay as they fell through.