Four cards banned a day into the Black Empire

Reign of the Black Empire went live on October 20. A day later, Blizzard pulled four cards out of constructed play: three in Standard and one in Wild. The bans are temporary, and Blizzard hasn't said how long they'll last.

"Our team has been keeping an eye on recent gameplay and discussion, noting that a few play patterns have proven more powerful than intended. It turns out keeping the Old Gods in check isn't easy."

That's Blizzard's whole explanation so far, posted on the official Hearthstone account. There are no patch notes and no nerfs yet. The cards are simply out of play until the team settles on a fix.

#What's banned

#Standard

• Bat Mask. Warlock, 8 mana, common spell from the Day of Rebirth mini-set: Set a friendly minion's stats to 1/1. Fill your board with copies of it.
• Divergence. Warlock, 5 mana, epic Shadow spell from Across the Timeways: Split a random minion in your hand into two halves.
• Reach Equilibrium. Priest, 1 mana, legendary quest from The Lost City of Un'Goro: Cast 4 Holy spells for Life's Breath, or cast 4 Shadow spells for Death's Touch.

#Wild

• Reincarnate. Shaman, 1 mana, Nature spell from Curse of Naxxramas: Destroy a minion, then return it to life with full Health.

#Why the Old Gods are the problem

The expansion's headline keyword is Old God. C'Thun, Yogg-Saron, N'Zoth and Y'Shaarj each come with four abilities. Instead of attacking, an Old God uses two of them a turn, and it can only attack once all four are spent. The brake on all of this is a deckbuilding rule: a deck may hold only one Old God.

Bat Mask is the clearest way around that rule. It sets a friendly minion to 1/1 and fills your board with copies of it, so one Old God becomes a board of them. Each copy has its own four abilities to spend.

C'Thun shows why that's a problem. C'Thun, Eye of the Empire is a 10-mana 12/12 whose abilities are tripled once you've triggered all four C'Thun abilities in a game. One of those abilities, Wrath of C'Thun, deals 7 damage split randomly among enemies. Before launch, Vicious Syndicate's day-one deck list already pointed at it: "we can simply activate C'Thun with 2 of the 7 copies we summon to the board with Bat Mask."

Blizzard hasn't said which pattern each of the other three cards fed, and we're not going to invent combos we haven't seen tracked. On paper, Divergence and Reincarnate both change a minion rather than answer one. Divergence splits a minion in your hand in two, and Reincarnate brings a minion back at full Health. Those are exactly the effects a set built around single, powerful Old Gods has to watch.

#What it means for your decks

• Decks that run a banned card are off the ladder in that format until you swap it out. Check your Warlock and Priest lists first.
• Nothing else changed. Every other card in the set is untouched, so C'Thun, Yogg-Saron, N'Zoth and Y'Shaarj decks are all still playable without the banned pieces.
• Dust. Blizzard's announcement doesn't mention dust refunds for the banned cards. We'll update this post if that changes.

#Track the new lists cleanly

If you track your games on Lolumen, log your rebuilt list as a new deck in the Tracker rather than editing the old one. That keeps the old list's record separate from the new one, and after a few dozen games Analytics will show you whether the replacement is actually better.

#Sources

• Hearthstone on X: the ban announcement
• Blizzard: Reign of the Black Empire is now live
• Out of Games: Hearthstone bans four cards after new expansion launch
• Vicious Syndicate: 45 decks to try on day 1
• Card text from the game's own card data.