There is only one card in Hearthstone: Heroes Of Warcraft that I make sure to include in every single deck I build. Emperor Thaurissan. The emperor is a legendary reward for completing the first wing of the Blackrock Mountain adventure. His effect? Passive: at the end of your turn decrease the cost of every card in your hand by (1). It’s incredible! Simple as that.
Including Thaurissan in a deck can completely change your mana curve on the largest possible scale. His strange ability lets him combine cards that otherwise wouldn’t work. You can use him to set up some of the best OTK’s available in game. For instance, a Priest deck could combine Thaurissan with Prophet Velen and two Mind Blasts for 20 burst damage directly to the enemy hero.
The only drawback is that everyone is aware of Thaurissan’s power. Other players rarely hesitate to kill him, so he often doesn’t last more than one turn on the board. It’s incredibly important to play him only when you really need him. Reducing the cost of legendaries like C’Thun for instance, is the ideal use of his passive ability.
If you’re looking for a legendary minion to add to your best decks, Emperor Thaurissan is a sure-fire choice.