Dragons do not breed true. They are under the Creator's edict that "No dragon shall lay dragon egg." When the Creator spoke this edict, His people rejoiced. They said that their grandcildren would live in a time with no dragons. The Adversary, however, saved his beloved creatures. Though unable to undo the Creator's curse, the Adversary found a way for dragon eggs to lead, sometimes, eventually, to dragons. Thus, the true dragons were saved, and the false dragons were spawned.
The creatures whose names are blue are true dragons. The others are dragon spawn.
Arrows indicate descent. Recursive arrows indicate creatures that breed true.
Double arrows point to groups of creatures rather than to individual species.
For example, dragon eggs hatch into various types of naga, all of which are sterile.