Just to answer your question, honestly.
We had this kind of suggestion waaaay back in DP's old-timey years several times. The answer to it is simple: Not possible.
By the way, this is kinda towards to Developer's side to make such thing happen.
I rather like them as bosses because they are unique and represented as their own master. Also that would kinda ruin the focus of the story and the game.
Osirans can't tame dragon gods. :^)
I hate fighting and or hurting dragons so I of course wanna tame them and see them as good. This game suppose to be about taming and over 600 dragons to tame yet I only see very few species for dragons and mostly 90% remodeled (birds are not dragons so idk why they called dragons.)