Hearthpwn

Mulligan hard for Gadgetzan Auctioneer and Shadowfiend. Play them together and use the coin or any spell to start up the draw engine, and then draw your whole deck for free on turn 2 or 3. All (most of) the minions draw cards, all the spells cost 1 or less and draw from Auctioneer, and Shadowfiend thus makes virtually everything free.

Once you have the draw engine down, play the cards that that will draw you two cards first. Coldlight Oracle, The Curator, Power Word: Shield. This is to give you the extra draw to cover for the win condition cards (which do not draw). The Curator is especially good since he will always draw you the Coldlight and either Malygos or a Drake, and he has taunt. Not much with a 1/1, but it's better than nothing. Use Flash Heal and Light of the Naaru to keep yourself alive and draw more. Power Word: Glory is handy on an opponent minion, or one that can attack this turn.

Your main win condition is Malygos + Prophet Velen + Faceless the Velen + Mind Blast for 40 damage. But there are several other winning combos as well, so pay attention to what cards you have at the time. Malygos can be Facelessed, The Azure Drakes have spell damage, Holy Smite gets buffed from these too, etc. It's quite likely that you'll have multiple win combos in the hand once your draw runs dry.

Expect the opponent to instantly kill your Auctioneer and Shadowfiend, so don't rely on leaving them up for a turn. Gotta get all your draw out as quickly as possible before the end of turn rope stops you.

If you get the Auctioneer and Shadowfiend, you pretty much always win before turn 5. If you are missing the Shadowfiend, then you might win by turn 5. If you don't draw the Auctioneer early, you probably lose.

Edit: Having played with it for a while, I find that Herald Volazj is basically a better Faceless Manipulator in this deck. However, that draw is still important to the deck, so changed it -1 Faceless Manipulator, +1 Herald Volazj. If you don't have Herald, then a second Faceless works just fine too.

Substitutes:
- Anything that draws cards or less than 1 mana spells will naturally work. Deathrattle draw is not as useful, but it can come in handy if you lack the cards.
- Emperor Thaurissan works if you can get him early, but once you get your draw engine rolling, he's a dead draw so I'd not include him.
- Malygos is a must have, but if you don't have him, Evolved Kobold might do the trick for you.
- Velen is also necessary, but if you have him and not Malygos, make sure you have Herald Volazj and both Faceless Manipulators. That can work.
- If you're lacking all these Legendaries, try a different approach. It's possible to make an Auchenai Soulpriest deck work and turn the healing spells against the opponent with this same draw engine. You'll want that spell damage too, because it does count when Auchenai converts your Restores to Damage.

Changes (11/1/2017):
- Skulking Geist is now a thing that exists, so reducing the number of 1 cost spells in the deck prevents counters from that. Added Circles and Silence to replace the missing 1 cost spells.
- Added Wrathion for additional draw, and rarely he'll get out your Malygos for you as well.