Ryoji misses Kai pretty much immediately after he goes back to his cave. It seems very lonely there, now, and dragon hoarding instincts kind of had him viewing Kai as 'his' so him not being there is very sad indeed. But he, too, learns a bit from the experience, and grows up a little more.

His attempts to learn more about how humans interact has been hard, seeing as he can't stay with Kai constantly (or much at all), but mourning is a concept familiar to both of their species. So at some point during a break in Kai's preparations, there is a little dragon perched on his window, waiting for him.