Hearthstone's third expansion pack may have just been outed. Data from the latest patch contains clues at Blackrock Mountain-themed DLC for the online card game.
According to Hearthpwn, the patch mentions Molten Core and Ragnaros card backs. The latter is a Ranked Season Play award, presumably for hitting Rank 20 in March. The Molten Core card back, though, is awarded for a "brm presale." Unfortunately, no images were included in the patch so we don't know what these backs look like.
The most popular guess is that "brm" stands for "Blackrock Mountain," a pivotal location in Warcraft lore. The fortress carved into the mountain is inhabited by the Blackrock orcs and black dragon Nefarian. Molten Core is the system of cavern below the mountain where Ragnaros the Firelord and his minions reside.
While Ragnaros is already a minion in Hearthstone along with a few of his henchman, there are plenty of other characters from Blackrock Mountain that aren't in the game yet. Nefarian, along with many of the bosses from World of Warcraft's various raids and dungeons set in the Mountain, could be viable cards for an expansion. Blizzard could round out the collection with some more generic minions like Blackrock orcs and Dark Iron dwarves.
I'm hoping that Blizzard doesn't just release these cards to the store, as they did with the Goblins vs. Gnomes expansion. It would be a lot more interesting if we got another single-player adventure like Curse of Naxxramas. In Naxxramas, players had to face defeat a series of A.I. bosses in order to unlock new cards for their collection. The special abilities of these bosses requires players to use unusual strategies to prevail. It forced players to try out seldom-used cards and learn how to debug their deck compositions.
Either way, this Blackrock Mountain expansion may come with a new board for the game. During Hearthstone's early development, they actually made a rough version of a Blackrock board:
The patch also references a third card back called "Golden Celebration." It's unclear whether it's related to the other two backs or this possible Blackrock Mountain expansion. Hearthpwn notes that it's added to a player's collection when a license is detected. Generally that means it's awarded by a purchase, be it a BlizzCon ticket or a Collector's Edition for another Blizzard game.
I assume that the "Golden Celebration" is a commemoration of Hearthstone's one-year anniversary. The game officially went live on PC and Mac on March 11th of last year. I wouldn't put it past Blizzard to give away a new card back to players to mark the occasion.