I would be happy to explain. But I think it would make more sense for you to hear the story from Zeno himself. [Again he doesn't want to complicate things.]
The original dragons served King Hiryuu. [They hardly live long enough to have lived for around 2000 years.] Our master is the reincarnation of Hiryuu.
[Although... the princess has stated that she's not him. Even still his blood calls out to her. Even if a difference in time is possible, which doesn't make much sense, even Kaya should know that King Hiryuu died so very long ago.
At the least he doesn't have a problem explaining about the others.]
Seiryuu and Ryokuryuu are indeed also real. [He recalls her comment on his hair.] Their hair matches the color of the dragon they exemplify. [See, he doesn't have aged hair...] Seiryuu is pure and determined with beautiful eyes. [Which he doesn't really...show off.] He has a pet squirrel named Ao, and she follows him everywhere.
[His little brother is enduring, no?]
As for Ryokuryuu he is independent, strong, and a little bit flashy. Also rebellious and difficult to understand at times. [And a scoundrel who visits questionable establishments, and is also saying weird things and flashing his skin...]
If he was here, however, I am sure that he would be happy to show you his skills. He rarely keeps his feet upon the ground.