Hearthpwn

My version of Warlock deck to beat Lich King. Completed it after 4th attempt.This deck includes only cards from Standard Mode, so you don't need to craft wild cards.

3 Phases to beat Lich King

Phase 1: Mulligan and Defense 

For this stage u need to mulligan your early game tools to protect your face and take as less damage as you can. The best ones are Mistress of Mixtures, Mortal Coil, Earthen Ring Farseer, Tar Creeper, Shadow Bolt. Make trades to keep your minions alive up to turn 6. By that time you also need to get one of aoe cleanings and destroy all Lich minions before he equips Frostmourne on turn 7, since it is very dangerous. Try to keep all remaining heal for stage 3 (since we don't have Reno Jackson).

Phase 2: Frostmourne and Board Dominance 

That's the most important part and you have to clear souls summoned from Frostmourne immediately. There are some ways to do this:

Play Twisting Nether on Turn 8. Kills all board, however you might still lose at tempo, since you spend a turn to clear all. Do this if don't have other options.

Play Corrupting Mist+Taunts on Turn 8. Safe variant. Better to play with taunt to lose much lower health. Better option, than Twisting Nether, because Lich King does not put any stuff when Frostmourne equipped. 

Play Doomsayer on Turn 7. The best option, since Lich King will always equip Frostmourne it and you get an ability immediately fill the board from Turn 8. Better to put one Taunt to not to lose 5hp.

If you get non of them by that time, but u have big board, you can try trade it, but it will be hard.

Phase 3: Trade and Offense

At this moment you start playing offensive by throwing stuff on the board. Try to minimize the damage dealt by enemy minions by trades. If it is not available, for e.g. your minions are frozen, put Taunts to keep your face. Use all your Heal for full. And the victory will arrive. 

General moments:

1. When you play Kazakus, always pick armor, if you get it. Extra health will play its role.

2. Play Alexstrasza for heal. Since we don't have Reno Jackson, use Alexstrasza as extra heal. Play it on Lich King when you can kill him only by using her as the resource of extra damage.

3. Violet Illusionist used to not to lose Health, while using Life Tap.

4. Tech cards you can change: Kabal Trafficker used for tiny chance to get Mal'Ganis. One of Giants can be changed, if you don't have one of them. Saronite Chain Gang used as spamming taunt. Can be changed on smth more worthy.

5. Other cards you can put in this deck: Despicable Dreadlord(i don't have him), Bloodreaver Gul'dan or/and The Lich King into one of/both giants. Tainted Zealot or Bloodmage Thalnos to increase Defile worth. List of some good cheap(dust) Wild Mode cards: Azure Drake, Sludge Belcher, Imp Gang Boss, Darkbomb.

Have fun!