Posts from Justice is a fan-made global mod.
Auto-translated
It would be better to use the term "chaplain" instead of "preacher" - chaplains were military priests.
Added 30 minutes later
Raider griffons, assault griffons, battle griffons, imperial griffons...
3) The wording "battle" is quite strange, considering that all creatures are combat units because they all participate in battles. Here, it might only be suitable for mages.
5) It's okay. However, both grades can be considered imperial, as they are both used by the empire. There seems to be some confusion. For some reason, the empire has a king and queen, not an emperor and empress, and the griffons are royal. But it can be assumed that Saint Isabelle changed everything to imperial.
ColouredText - список заклинаний и их уровень в описании существ-колдунов
ColouredText - список заклинаний и их уровень в описании существ-колдунов
And do your red griffins, like in the original, have the ability to attack everyone in a line? Then you could call them "Rukh birds." Remembering that these birds tend to lose their steel feathers in flight, thus injuring people. I don't know how lore-friendly that is for Ashan, though.
It's strange how griffins become completely different birds when upgraded.
ColouredText - список заклинаний и их уровень в описании существ-колдунов
ColouredText - список заклинаний и их уровень в описании существ-колдунов
Added 3 minutes later
In WGE, they are called storm griffons.
ColouredText - список заклинаний и их уровень в описании существ-колдунов
Why not others... They might have the same griffin-like body structure. If it isn't forbidden by the Ashan lore.
The World of Spirits is divided into elemental worlds, each of which is inhabited by special types of spirits and elementals, the most powerful of which are dragons. The Bird of Thunder, known in the writings of the Seven Cities as the Roc, is one of the greatest spirits of Air. Being bound to the material world, the Bird of Thunder causes storms and hurricanes with every flap of its mighty wings. Most often, the bird is summoned by mages or priests of Ialat through a complex ritual, but sometimes a Roc egg appears on its own in the place where lightning strikes the ground.

Added 1 minute ago
P.S. source http://ru.mightandmagic.wikia.com/wiki/Птица_грома_(HoMM_VI)
Блистает там воздушностью прогалин.
Но между кедров, полных тишиной,
Расщелина по склону ниспадала.
О, никогда под бледною луной
Так пышен не был тот уют лесной...
In WGE, they are called storm griffons.
What if some fiery/swift/ardent ones?
2) They are not fast.
3) It might work.
ColouredText - список заклинаний и их уровень в описании существ-колдунов