Hearthpwn

POST-KARAZHAN UPDATE: The exploit that lies in the core of the deck where the AI won't attack a taunt minion that has Kel'Thuzad to back it up has been fixed and it's no longer working. KT is still very powerful and may help you win the game as some players report but it's no longer a reliable win condition. I'll do some testing to see how the new cards since the deck was originally released can improve it.

I tried all kinds of decks in order to beat that annoying boss and ended up building my own deck that succeeded in the very first try. I played 6 more times to check it's consistency and I won again in 4 of them. 5 wins out of 7 tries sounds pretty good to me.

First things first. You probably know this already but if Maloriak opens up with Release the Aberrations! give him the finger and concede. It's almost impossible to come back from that (one of my losses was from exactly that).

Now that we got that out of the way we can proceed with our own agenda.

The whole idea of the deck is to exploit a weakness of the AI - skipping it's turn when there is a taunt + Kel'Thuzad on the enemy side of the board (this is nothing new, it was used in other bosses as well, I just never saw it suggested for this one in particular - all decks seem to focus on minions that end up with high attack after the swap).

This means that we are aiming to have a very specific combo on turn 9/10 (or 7/8 if you managed to play Emperor Thaurissan earlier) and more importantly - to stay alive until then in order to make use of it. As you probably guessed we are going for Kel'Thuzad and a cheap 1 mana taunt (Goldshire Footman, Tournament Attendee or Annoy-o-Tron depending on their respective costs at the time). Once you get these out it's pretty much game over. The only real threat to your board in this state are the two Polymorph spells Maloriak uses, but if RNG isn't entirely against you you should be able to stomp over him before he manages to even make an attempt to come back.

Now that we know what our win condition is we need to take a step back and look at what we have in our bag to get there in once piece. Our deck makes use of a bunch of cards to help us stall the game until we have enough mana and our combo pieces:

• Silence - to remove the scary buffs from a fat minion. If you can take out a Sludge Belcher in this way - good for you.
• Mass Dispel - because sometimes a single silence isn't good enough. Especially after the bastard got those nasty Abberations out or hit your stuff for 4 with his Imp-losion.
• Kezan Mystic - because Priests don't usually have access to Counterspell and it's especially good against the Release the Aberrations!.
• Thoughtsteal - because sometimes your Kezan Mystic steals Duplicate but we want our Counterspell as well.
• Flash Heal - You will be glad you were able to heal for 10 to survive one turn for your combo.
• Mind Control Tech - because 3 damage off your face can be a life saver.
• Various buffs for our minions to speed things up damage-wise or use for crowd control.

Important note: Heals and stolen cards / creatures can take you only so far. Our most powerful mechanism to survive until the combo turn are the numerous silences. Maloriak tends to run a lot of small (usually) shitty creatures that get buffed to formidable threats. When silenced though, they are back to their normal negligible little selves, but most importantly - they occupy valuable board slots, so he can't pull more stuff to buff. Try to keep many small, silenced minions on his side to deny him the real estate and damage output - Imps and Abberations seem to work best, since they take a lot of slots.

Mulligan: You are usually looking to have Mass Dispel, Silence, Flash Heal and/or Shadow Word: Death in your starting hand. If you get Kel'Thuzad along with a good two of the other cards listed above - keep him.

That's pretty much it. It may take you a couple of tries but it should be a pretty easy victory in the end.

Good luck!