Mulligans
The deck is supposed to survive aggressiv decks with the big amount of removal like:
Defile Hellfire Lesser Amethyst Spellstone Lord Godfrey Shriek
And stabilise with:
Voidlord Bloodreaver Gul'dan Skull of the Man'ari and other taunt minions
Afterwards the main purpose of the deck comes:
Void Contract Should destroy the main part of the opponents deck, including his/her combo pieces.
Your aim is to discard Baleful Banker and Gnomeferatu in order to get it back with Soulwarden and go infinit.
This deck counters agressiv and cobo decks, especially Hakkar Druid and is a new version of control Warlock.