The Wyvern Knight can use a breath attack, so jump underneath its head as soon as the battle begins to avoid this. Cast Herakles and then attack its head, body, or neck with an edged weapon buffed by Prostasia. It will drop the Chest Key on its defeat, which is required to open several very useful treasure chests.
[view·edit·purge]A wyvern is a medieval European mythological winged creature with a dragon's head, reptilian body, two legs (sometimes none), and a barbed tail. They appear in many crests of Europe's ancient families, symbolizing strength. The word wyvern comes from wivere, which means serpent.