Viper venomous silver sword is a silver sword and is part of the Viper School Gear introduced in the Hearts of Stone expansion for The Witcher 3: Wild Hunt. However, unlike other items in the Viper School Gear set, this one does NOT have a diagram and the sword can only be obtained during the quest Whatsoever a Man Soweth… by challenging Master Mirror. The sword is found protruding from a stone in the puzzle world.