Kai Canarbis encounters/contests the Cold Chaos Dragon for the first time ever in The books never mention what colour the Dragon is, but I believe it would either blue or white. He wouldn't be green, like Lord Gabbubunto, as he's a very different beast.
Hydrophius (Water Dragon) is a Morphian Morphiped. Repetitive-sounding, huh? Well that just means that it can change shapes, spending most of its time as water itself, with a core at the center, allowing it to change whether it has wings, two legs, or four legs! If you are a Hydrophius, you are a gentle, but powerful, go-with-the-flow kind of person. You watch over from a distance, and spend much time on thoughts and whimsy.