Breeding dragons seems very wrong. Dragons are the weapons forged by the gods in the godswar, and there is no evidence that any dragon has ever reproduced. I tend to think that dragon reproduction is physically impossible. Any dragons that enter the game would either have to be awakened from their slumber and taken out of storage, or brought back from the dead. Either way would involve complex rituals rather than breeding.
Considering that all the lore behind it makes it clearly a secret religion, I tend to think that no one should be able to adopt it.
It might be nice for at least some of its disciples to be invisible. It is generally subversive, s it may be appropriate for dragon priests to be uncontrolable. A permanent promotion with the effect of Enraged may be appropriate. Making the units AlwaysHostile could be fun too.
Whatever dragons you may add, they should not be as strong as those already in the game. (Although I tend to think they should all be made stronger.) No beast (or even archangel) is as strong as Eurabatres. All dragons are but poor imitations of this greatest of all creations.
Not every god made a dragon, but some made many. We know Eurabates is the only dragon of Amathaon, but the other dragons in the game might have siblings. I'd guess that they all have the same color as the others created to serve the same god.
I tend to think that Bhall may have created many such beasts, but Acheron (who rebelled against her as soon as he was created) was the greatest.
We know there was a Blue Dragon who was slain in the Age of Ice, and that a Blue Dragon is somehow associated with Luciaque's Pool. It isn't clear whose he was, but I tend to think he was a creature of Danalin who (like Leviathan) was driven insane by whatever destroyed the Aifons and was killed after an uncontrolled rampage that was very much out of his real character.
Since Sucellus did not intend to fight in the Godswar, he likely made no dragons even if he created the Big Apes to guard his lands. If he does have a dragon, I'd suspect a green dragon that breathes acid/poison and not fire.
I have trouble imagining Sirona or Arawn creating any dragons. Esus is also opposed to such a direct weapon, so he would make much more subtle beasts instead.
I have no real basis for this, but I think it could be cool for Lugus to have a Chrystal Dragon, whose body is luminous and entirely transparent.
Since Agares created no Angels, I highly doubt he made any dragons either. However, just as he managed to assemble the largest army of angels through corrupting the creations of the other gods he may possess the largest arsenal of dragons too. I rather like the idea that he possesses another Golden Dragon (well, a Black-and-Gold dragon) that was created from Eurabatres and the Black Mirror just as Hyborem was created from Cernunnos. Eurabatres may have just been Rabatres before adding the Eu (Greek for Good or True) to denote that he is the real Golden One and Agares greatest dragon (Disrabatres?) is an inferior copy.
thank you for your help 
