Hearthpwn

For those who don't have dozens of legendaries to choose from, I won with this deck after four or five tries. Mulligan any minions you get besides Kel'thuzad, try to get some cheap removal.

Play no minions before turn seven or eight as their main role is to protect Kel from hero power removal. Initially control the board with removal, trying to get as many two or three for one trades as you can. You can wait a turn to maximize your flame strikes by accepting a few hits to the face, but be careful of the wind-fury ogre that can get buffed.

As usual, Kel is what gets you the win so once he is in your hand and you can afford him, make sure the board is looking reasonable and drop down your creatures. Put down Kel next turn and use your minions to remove the board since they will target Kel. Next turn if your not unlucky to loose Kel to hero power use Faceless Manipulator on Kel (or Echo of Medivh - slower/inferior). Make sure neither Kel gets too low on heath by killing one of them yourself if needed.

Naturally, if you have superior cards, make the appropriate substitutions. Also, remember that the first minion to die is the first minion to be re-summoned by Kel, so if your board is full and you need to create a slot to play another minion card, make sure you order your minions appropriately so you keep your superior minions on re-spawn.

Turn nine Kel and mirror image is likely your strongest chance to get there as the mirror images have a good chance to respawn and offer great protection.