Blue dragon

Blue Dragon are the third strongest dragon in the game right behind Red Dragons and Black Dragons (This is not including the Metallic Dragons. They are a powerful beast due to their dragonfire attacks which can hit for over 50 damage. Due to this an Antifire Potion, Anti-dragon Shield, or Dragonfire Shield is advised to kill them. 

Locations:
Taverly Dungeon (3)

Ogre Enclave (6)

Heros' Guild (1)

100%