Ruby

History
Ruby was a dragon living in Dragonland until she decided to rise against Shang-Tsei who used his Dragonstone to control other dragons, hurting them; Ruby stole the Dragonstone and ran away.

Ruby was found and adopted by Josie, who from then took care of her. Josie and Ruby lived together ever since, protecting each other in front of danger. Ruby lived without Josie for a while after the episode "Runaway Dragon", where Josie decided it was better if she kept Ruby in Chronos rather than on Earth. Ruby didn't appear again until Josie decided to stay in Chronos for unrelated reasons in the episode "Josie the Pixie Witch".