DragonBlade

Fact: Dragon's scales are as hard as platinum, and their blood is poisonous when it reacts with metal. This simple adaptation has given dragons a nasty reputation for hoarding precious minerals in their lairs. However, stealing another's gold marks your name on a wanted list. Knights and Vassals everywhere went searching for these thieves, hoping to reclaim their quarry. They have a slight advantage- the poisonous steel-blood alloy is poisonous even to the dragons.
Here's the paradox. How do you get to it?

Rendered in Photoshop.