Your main's favorite Hearthstone card

http://blogs-images.forbes.com/insertcoin/files/2014/12/hearthstone1.jpg I have met a lot of people who enjoy both LoL and Hearthstone, personally I can't wait for every Wednesday for the Tavern Brawl, and now Thursdays for Karazhan wings, but if your LoL main played Hearthstone, what would be that one card they would put in every deck?

http://media-hearth.cursecdn.com/avatars/252/290/22323.png FOUR!