cmax110

I am thinking this is the other student, transformed into a puppet or zombie or something like that

when the bottle contains a liquid

*from sea to mountains

He could leave the wall to bait his other world crossing self, to get a glimpse of his path before true returning

Similar to the Xuan Yuan mirror being sentient and searching for it's own path, the disc will likely do the same.

isn't he a rock? What's he mean his kind

wasn't he 5 hours away?

Probably the same way you're connected to your true self