Mulligans
General Mulligans
The Mulligan here is all about establishing board control in the early game, while allowing a few Life Taps to get more resources before the Taunts come down. Felguard is not here as it is ideally a more late game play, so as to not offset you mana development.
Stall the Early game with taunts and removal.
Win the occasional game against quest mage with Gnomeferatu removing Archmage Antonaidas.
Youthful Brewmaster has may uses; extra battlecries from Gnomeferatu/Earthen Ring Farseer/Gluttonous Ooze, “heal” big taunts again like Tar Lurker.
Felguard may seem strange, but it’s the biggest taunt Demon available to Warlock that doesn’t destroy your hand, and comes back with Bloodreaver Gul'dan.
Dirty Rat can be played early against aggro; against control it can be played late and combined with either Twisting Nether or Siphon Soul.
Bloodreaver Gul'dan is ideally saved for when you get to fatigue. always try and bait out boardclears before dropping this.