According to a recent Penny Arcade Expo East 2014 announcement the company made, players will fight through five unique wings of the Naxxramas necropolis run by the archlich Kel’Thuzad (whom World of Warcraft lore fans should be incredibly familiar with). They’ll be fighting against campaign-specific bosses with their own special cards and skills. One example includes the cauldron master Heigan the Unclean, who has an Eruption hero power which deals two damage to the left-most enemy minion and a unique Mindpocalypse card where both, he and his opponent draw two cards and gain a Mana Crystal.
Players will get a new card for defeating him (and other unannounced bosses), as well as a guaranteed Legendary card for completing a necropolis wing. Speaking of which, players will get to acquire up to 30 new cards in the expansion. Since the expansion is all death and necromancer-themed, most of the cards seem to be leaning towards the Deathrattle mechanic (i.e: If a card goes to the graveyard, its Deathrattle ability activates).
Case in point, the Dancing Swords minion card cost less for high health and attack, but gives an opponent a free card when it dies. The legendary card Baron Rivendare doesn’t cost much, but it has huge health and lets Deathrattle abilities trigger twice.
The expansion will also feature a necropolis-themed game board and new Class Challenges for gold-earning and class-specific cards-getting. The campaign will open over the course of five weeks, with each wing opening one by one. The first one, called the Arachnid Quarter, will be made free for all Hearthstone players. The rest of the wings will need to be bought either with real money or in-game gold.
There’s no release date for Curse of Naxxramas yet, but it’ll be released simultaneously for the PC, Mac and iOS devices. In the meantime, those with Australian, Canadian and New Zealand Apple App Store accounts can check out the newly soft-launched iPad version of the game.