[Gradually, the sounds of birds and other animals, water running in the distance, and their own footsteps fade into natural ambience. Reisi hears the faint scratching just before hearing Kurosaki's voice and casting a glance back for confirmation. Ahead and left. He focuses his attention in that direction and can more clearly hear the sound—it's oddly repetitive and persistent.

Just as he's about to ask about proceeding, Tenjoin asks about the masks' composition. Reisi pauses, maintaining his focus on the scratching rather than turning back.]

Did you find another lead, Tenjoin-kun? [He doesn't think the other shinki would spontaneously ask about something like that.] The sound seems fixed for now, but we may be too distant to rightly determine its movement.