This is Grockle from the third book, Fire Star, in Chris D'Lacey's the Last Dragon Chronicles. Major spoilers here so I can't give too much away, being it the third book. But Grockle... is this dragon....
He was supposed to be Liz Pennykettle's son but he was quickened by David's friend (at that time) Zanna. The sibyl, Gwillanna, made him a real dragon instead of a little boy with dragons in his genes.
Later, that star looking speck is the Fire Star. A portal to a different dimension, the world of the Fain. But that's too many spoilers for now. Go buy this series on Amazon, it's amazing!!!!