Booster Dragon is the Rulishia's cute little dragon partner in the Demon Chapter. He has very large anime-style eyes, and makes very cute sounds at times. He also seems to be taken with wearing a rocket-pack as wears one to fly, mostly to aid Rulishia in air attacks. He can use his own wings to fly too, but he favors the rocket-pack as you might have guessed from his name and being a very young dragon, flying is difficult for him. Unfortunately, even for a dragon, he is not strong enough to directly assist Rulishia in battles.
As for his background information, he has been with Rulishia since she was a little girl. He doesn't physically look older since then but then again that could be because that was only a few years ago and dragons don't age in the same time intervals as humans.
(Source: absoluteanime.com)