Kotetsu replies without thinking, at first, not entirely registering that he's just been replied to. "Even I know clouds don't work like that. There must be something..."

And then he falls silent. His eyes go wide. Because it's only then that it does sink in that the monster standing beside him did, in fact, reply to him.

He whirls around to face Asriel, tapping a finger against his own chest. It takes him a few false starts of stumbling and stammering, but eventually he manages to force out a coherent sentence.

"You can see me?!"