Wyverns are wild creatures, usually medium sized pelican like creatures with scales, they have massive sacks on their throat that contain a load of poison for hunting or combat. The creatures enjoy roosting on cliffs.
Despite their bestial appearance, the wyvern actually has a great intelligence, and are beloved as pets to knights and nobles in the Kraezian empire and as flying war-beasts by this same empire.
There are different species of wyverns in fact, the most common is the venomous swamp wyvern, the kind kept as pets, the hell-fire wyvern, a massive and dangerous variant seen rarely in volcanoes, and resembling more a massive fire breathing dragon, steam-belch wyverns, larger, more unbridled blue wyverns that breath steam. They are similar to a smaller kind of hell-fire wyvern and are used as guardians of large godly temples. The other two variants are the blood-talon wyvern, which has talons known for being sharper than steel daggers, and the glory-feather wyvern, an extremely fast species that is used for bets and races.