This monstrosity starts with 150 health, but unlike in Naxx, Alexstrasza is legal in this adventure. As such, a straightforward Freeze Mage build will easily get you through this one. Just like Chenvalaa, the emphasis on Freeze cards means the boss will have trouble dealing damage from hand, making Doomsayers very reliable, sometimes even without a board freeze effect. Playing Archmage Antonidas on an empty board is also surprisingly safe. 15 damage is all you need post-Alexstrasza, so feel free to use everything else in the deck in order to clear the board. A word of caution: since Chenvalaa has a lot of Molten Giants at its disposal, you don’t want to do any face damage to it before playing Alexstrasza, and you should only do so when you have everything ready in your hand to finish it off the following turn.