Do you remember the Rastakhan's Rumble trailer that showcased Hir'eek, the Bat? It showed a board being swarmed with an army of 5/5 minions, all of them copies of Hir'eek, ready to drain the enemies dry. Despite how splendid this looked in the footage, in practice the card is almost always extremely underwhelming and difficult to make work. So, what hoops does one have to jump through in order to use Hir'eek as their win condition? The answer is a quite a number of them, but allow me to be your guide through this bat cave.

Essentially, this deck makes use of the wealth of board control tools accessible to the Warlock class as of Rastakhan's Rumble, and with each removal serving to remove a variety of  different board states we are able to use the rarely seen "Shriek" card. Ordinarily, Shriek is overshadowed by better removal options, and most decks that might otherwise use it would suffer heavily from its discard drawback. However! Shriek is a powerhouse in this deck, because your win condition, Hir'eek (after been buffed with Soul Infusion once or twice), will almost never be discarded, so Shriek away! Take a some care to not throw away both Soul Infusions, though.

Like Shriek, the incredibly slow buildup into a massive board flood structure that this deck possesses enables it to make good use of other very niche removal tools: Corrupting Mist, Curse of Weakness, Shadow Bolt and Drain Soul. Couple these with more popular and widely applicable removals like Defile, Lesser Amethyst Spellstone and Hellfire and you have all the removal you need to outlast even the most aggressive decks. Similar to Mechathun Warlock, this deck features several card-cycling cards that will likely draw you into at least one Soul Infusion, if not two, and Hir'eek by turn eight. Do not worry if you have not drawn Hir'eek by this point, because two Twisting Nethers and Bloodreaver Gul'dan, a card powerful enough to be justified despite the lack of demons, exist to help you calm the board.

This deck's worst matchup, by far, is Priest. I will argue that is list can be competitive, but Psychic Scream and Mass Hysteria will debilitate you at best and destroy your win condition at worst. Should you match up against a Priest, hope that they do not have a Mass Hysteria to clear all of your bats, because this will almost certainly leave you with nothing left. Having said that, this is a decent "stall deck" that buys you time, controlling the board until you're able to unleash your bat legion. Cycling into your combo should be your top priority with board control being a close second.

Tech Choices:

Aggro: -2 Twisting Nether, + 2 Voidwalker

Control: -2 Drain Soul, + 2 Voidlord