
it was mentioned many many chapters ago, either at Kija's first appearance or when the dragons were finally united and went to visit sensei (the priest). At some point Yona mentions that she couldn't be Hiryuu because she wasn't related to them because she was from a different tribe (Sky), sensei also mentions that royal family changed many times during the many centuries that past. All the tribes at some point became the royal family. That's why there's a lot of theories around that say Hiryuu's bloodline came from the fire tribe.


