The Witcher Bestiary - Wyvern
Wyvern Occurrence: Wyverns live in the wilderness or near human settlements; they are a natural element of an ecosystem; they are prized by druids, who tame them.

Immunity: Resistant to stun and poison attempts.

Susceptibility: Sensitive to silver and Ornithosaur Oil.

Tactics: They dive at their opponents, try to knock them down and poison them with venom.

Alchemy: Toxin and wing membrane, venom glands.

Wyverns are unlucky to be frequently mistaken for dragons. Seeing a reptile approaching a flock of sheep, peasants panic. They expect it to breathe fire, massacre everyone and abduct the local virgins. While it is true that wyverns hunt sheep, they neither breathe fire nor lay waste to whole villages. And they are completely indifferent to virgins.