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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.
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P.S. source http://ru.mightandmagic.wikia.com/wiki/Птица_грома_(HoMM_VI)
... И древний лес, роскошен и печален,
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...
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...