The Wyvern is a very dragonlike creature, although it only has two legs. It is a branch dragon, Not a main dragon. meaning its not really a true dragon (which has supperior intelligence, power, etc) but a creature that is closely related to the true dragons, and falls under a sub-specie so to speak.
InsteadUsually, instead of breathing fire, the wyvern has breath so poisonous, it brings on outbreaks of the plague. Its tail is so sharp, it can leave a man with stumps where he once had limbs. Its legs are as thick as tree trunks, its nails are sharper and stronger than railroad spikes, its bones are hollowlight in weight yet stronger than concrete, and it has an appetite so huge, it can devour entire small villages in one sitting.
Wyverns inhabit caves, the same places as most dragons. In fact, dragons sometimes bully wyverns out of their homes, but then the wyvern aquires a thirst for revenge. It will hunt the dragon, and strike when it is at its weakest.
Wyverns cannot speak, but can scream and roar. They lack the grace and intelligence of dragons, but that is a small price to pay if you are as vicious and bloodthirsty as the wyvern.
They do not make good pets, since they have a thirst for human blood as soon as they turn three years old.
They are smaller and usually nimbler than dragons, so they can fly larger distances and are more nimblemanuverable in close distance aerial battles, although they don't have arms and only have two wings with an opposable thumb each.
Weyverns live usually shorter lives than dragons other.