Hearthstone Fall of Ulduar Anomalies Explained, How Does Cho’Gall, Twilight Chieftain Work (Updated)

Update: A full list of Anomalies was released in 27.4 patch notes – you can find them at the bottom of this guide!

Blizzard has just announced the upcoming Hearthstone mini-set. It’s called Fall of Ulduar, and on top of the regular card drop, it adds a brand-new mechanic… to nearly all Constructed/Draft game modes (Standard, Wild, Twist and Arena – they will not appear in Duels, possibly due to some conflicts with already-wacky Duels effects). The mechanic is called “Anomalies” and it was already added to Battlegrounds in the last major patch (27.2) albeit in a slightly different form.

The announcement has already divided players. While some seem to enjoy the fact that the game will get more diverse and you will have to adapt on the fly, others don’t appreciate extra RNG and think that Anomalies belong to the ranked game modes and should stay in Twist or Tavern Brawl. But what are they and how do they work exactly?

The idea behind Anomalies is that at the start of the match, you might roll a random special effect that affects both players. The effect will be known before the mulligan, so both players can prepare for it. On turn 1, the effect will activate, potentially changing the way the match is played quite drastically. Or not at all – while some Anomalies will really make the match way different from a normal one, others can be pretty much ignored.

While you might think that since an Anomaly affects both players equally, it shouldn’t really change the outcome of the game, the idea is that different decks might benefit from a certain effect to a different degree. For example, the Anomaly adding Yogg-Saron, Hope's End to both players’ hands will be significantly stronger in a deck running tons of spells than in a minion-heavy one. Anomaly that increases starting Health by 5 will benefit slower, Control decks way more than aggressive ones. And, for example, Anomaly that makes players Discover new Hero Power will destroy decks that are built around their basic one (e.g. Hero Power Druid). You can find a full list of Anomalies at the bottom of this post – while some of them are balanced and should affect both sides equally, most of them will benefit one side more than the other.

To activate Anomalies, you need to play Cho'gall, Twilight Chieftain in your deck. Except…

Anomalies Until Patch 28.0

Here’s the most controversial part of the update. After the mini-set launches on September 19, the anomalies will automatically “corrupt” all of the aforementioned game modes.

  • For the first week after the patch (until September 26), anomalies will appear in 100% of the matches. Yes, every single Standard, Wild, Twist and Arena match will have a guaranteed Anomaly.
  • Then until Patch 28.0 (the next expansion’s patch, probably ~2 months after the mini-set), Anomalies will appear in 25% of the matches. So every fourth game will have Anomalies no matter if you play Cho’gall or not.
  • If one or both players run Cho'gall, Twilight Chieftain during this time period, they can activate a SECOND Anomaly.

Of course, Anomalies won’t activate by themselves forever. Bless Yogg, but that would be too much.

Anomalies After Patch 28.0 (Cho’Gall)

After Patch 28.0, Anomalies will no longer appear by themselves. The only way to activate them will be through Cho'gall, Twilight Chieftain.

  • If Cho’gall is in either player’s deck, the game has a 25% chance of starting with an Anomaly.
  • If Cho’gall is in both players’ decks, the game has a 100% chance of starting with an Anomaly.
  • After the initial event has passed, there will be no chance of having two Anomalies active at once.

Given that Cho’gall himself doesn’t seem like a great card (if you play him in a competitive deck, he will most likely be the worst card in your build), I wouldn’t expect to see Anomalies in high ranks that often in the future. Unless something changes, you might sometimes see them in Casual or at lower ranks, where people will play the card for fun and not competitively.

Full List Of Anomalies

Here’s a full list of Anomalies Patch 27.4 is launching with (20 in total) – both in text and visual formats. There’s no telling whether more of them will be added in the future.

  • Approaching Nightmare – Both players start with Yogg-Saron, Hope’s End in their hand.
  • Army of the Corrupted – The first minion played on each player’s turns costs (1) less.
  • Control the Makers – Both heroes have +1 Attack on their turns.
  • Driven to Excess – Whenever a player ends their turn with unspent Mana, they draw a card.
  • Driven to Greed – Whenever a player ends their turn with unspent Mana, they get a Coin.
  • Fast Track – Reduce the Cost of all cards in both players’ starting hands by (1).
  • Fortifications – At the end of each player’s turns, give a random one of their minions +1 Health.
  • Gift of Gluttony – Both players start with two more drawn cards.
  • Light in the Dark – Both players’ Hero Powers cost (1) less.
  • Opportunity Knocks – The first card drawn on a player’s turn is one they can afford to play.
  • Seeing Double – Both players start with 2 cards copied from the other players’ hand.
  • Severed Souls – Both heroes start with +5 Health.
  • Shifting Fate – Both players start with Gear Shift in their hand.
  • Shifting Futures – Both players start with 2 copies of Shifter Zerus in their hand.
  • Spread of Corruption – The first spell played on each player’s turns costs (1) less.
  • Surging Inspiration – Both heroes start with upgraded Hero Powers.
  • Twist Reality – After a player plays a card this game, shuffle a copy into their deck.
  • Uncontrollable Growth – Both players start with an extra Mana Crystal.
  • Unimaginable Horrors – Both players Discover a new basic Hero Power on their first turn.
  • Your Eyes Betray You – Both players’ cards are Golden.



A Hearthstone player and writer from Poland, Stonekeep has been in a love-hate relationship with Hearthstone since Closed Beta. Over that time, he has achieved many high Legend climbs and infinite Arena runs. He's the current admin of Hearthstone Top Decks.

Check out Stonekeep on Twitter!

Leave a Reply


  1. Asperkraken
    September 19, 2023 at 1:50 pm

    Good thing I hit Legend before this dropped. Ugh. You would think they would just do some buffs/nerfs to change up the metas again but RNG? This seems like a Tavern Brawl idea that somebody decided would be GREAT for Ranked.

    Worse off, as you mentioned in the article, some matches will be downright unwinnable if certain anomalies happen. Of course, if you’re tired of playing against Even Shaman (sorry/not sorry), it will be hilarious watching them lose their hero power.

    Oh my, this will be madness. Can’t wait to read the raging which usually matches said madness by 10x.

  2. KonuTech
    September 19, 2023 at 9:46 am

    It is just an enforced event disguised under the mask of a card. “Move Along, Nothing to See Here”

  3. DemianHS
    September 18, 2023 at 11:01 am

    I’m here for the other 17 anomalies. 🙁

    Times of clown fiesta RNG will come. Pray Yogg my friends! ????

  4. Strangiii
    September 13, 2023 at 1:31 am

    Instead of trying to destroy constructed with this nonsensical RNG fiesta for more than 2 months, they should keep the “each match has an anomaly” for one week and afterward, they only activate with Cho’gall.
    I don’t know what they were thinking, especially with this “Wild cards in Standard” event from a few years ago.

    Events that last for 2+ months and change the state of the game/format drastically are never going to end well.

    • Stonekeep - Site Admin
      September 13, 2023 at 7:21 am

      I agree, I think that the initial week is good. Might be fun, and if it’s not fun for someone then skipping one week is not a big deal. I think that those kinds of experimental events are good for the game, because otherwise it might get too stale.

      But the ~2 months after is way too long. People who like Anomalies won’t be happy with only 25% (and they can just run Cho’gall anyway) and for those who hate them, having to face them 25% of the time will feel horrible (especially rolling a few of them in a row). I think that it adds more negative feelings than positive feelings.