Mulligans
No new cards are needed. The deck is still strong. The current meta is kick-started by a 78% win rate in 23 games from Diamond 5 to Legend.
The goal of the deck is to get to Bonelord Frostwhisper and Cage Head as quickly as possible during the game and make a killer combo. Until then, we play a regular DK on plague. Don’t skimp on spending Death Growl Dead Air Yelling Yodeler on regular Deathrattle minions, especially if you need card draw. You can place Bonelord Frostwhisper even when Cage Head is not yet in your hand, but only if you are sure that you will get it in 2 moves. In between, play heavy cards The Primus and The Scourge to maximally force your opponent to think about clearing the board and surviving rather than using his strategies. After setting these cards for 0, play Defrost Chillfallen Baron Sir Finley, Sea Guide to find Cage Head and destroy your opponent.
Made almost this exact list early in expansion. It’s a lot of fun.