Why Shaman?

I noticed that the priest decks were centred around Lightwell in order to stay alive and maintain board control. Having the misfortune of not owning any, I turned to a Shaman deck. While vitality totems aren't as good as lightwells, they kept me alive long enough to build up board control while consistently removing Brood Affliction cards. Shaman's cheap and excellent removal cards allow you to stay in the game long enough to play and protect your minions.

How to play this deck

Vitality totems are vital to this strategy. Get them early. Otherwise just get low-cost cards.

Each turn you will want to remove non-green/black Brood Affliction cards from your hand; Green because you're going to have a hard time surviving, never mind attacking early, and Black quickly fills up his hand, which nullifies the effect anyways.  You can try to bait out big AOE cards like Flamestrike with totems.  Once you feel like you can close out the game, perhaps with heavily buffed Lightwarden, you can start tossing out the Greens and Blacks.

I personally managed to beat Chromaggus first try with this deck. It's definitely not perfect, though, and many of my cards turned out to be redundant so feel free to modify it as you like.

Thanks for reading!