Dragons are divided into the following: primordial, ancestry, legendary.
Some of them obtained from using souls, commonly 70. fragments and eggs. Fragment dragons like Flakbeard/Crisopeia crafted using pirate/kami dragon egg fragments.
Inora, Erel, Yorinn and many others hatched from eggs.
There is also golden eggs in game that allow you to hatch any of them w/o using coins. Primordial dragons required diamond eggs to craft them.
A few ones dormant dragons like selene hatched from egg bought at store.
All of the dragons can fly with 100 glide movement speed, except Scintilla.
The most valuable and rare of them is a Primordial that limited to 5 despoled divinity per week.