Wyvern's Tear

It is sometimes dropped from a defeated Wyvern.

Description
"The wonderous liquid of a dragon's eye. Collect it from each species and you may alter the rewards from defeated foes. Details unknown."

Effects
The item's description implies that, if the Arisen carries all three tears (Drake's Tear, Wyrm's Tear and Wyvern's Tear), the likelihood of enemies dropping rare items is increased. The exact adjustment is unknown.