Well, if I'm not wrong, I think the dragon is the one they found injured while they were escaping from the enemy and Chihaya is the pup(child?) from the tyger that helped Naoe and his sister when they were young. I think.
Ah, yes. I remember now. I didn't realize that Chihaya was the cub of that tiger. Either way, I love those two! <3

You know, I am super curious on what Naoe's full past was. How did he become friends (SPOILER ALERT) with a dragon? And how was he able to become friends with Chihaya (his cat)?