Wyvern

Wyrens are winged demi-dragons capable of flight, although it was the subject of academic debate whether to categorize them as demi-dragons or beasts. Although wyverns breathed fire like dragons, they had no front legs and were smaller, weaker and more simpleminded.

They are still a significant threat. Hunting a wyvern requires a reasonably sized, trained team to attack its nest. It is extremely difficult to secure a vicoty on flat land against a wyrvern when it had absolute control over the sky.

It was also said that some rare wyvern could speak the language of dragons. These wyverns served the dragon and lizardmen exalted them. As for wyvern in the Beast wood's mountains, it was one like a beast: it had low intelligence and was unable to talk.

Summary
To be added later.