Breakthrough•Attack

Is Breakthrough good in Slay the Spire 2?

Breakthrough is a common Ironclad attack in Slay the Spire 2. In combat it resolves as: Lose 1 HP. Deal 9 damage to ALL enemies. It’s a dependable, middle-of-the-pack option, landing at C tier in our rankings.

Across 10 recorded runs, decks running it win 20.0% of the time, comfortably clear of the 12.6% average, by 7.4%. It’s a more selective pick, turning up in just 1.9% of decks that could run it. Ironclad players keep it in 18.4% of their runs, so it’s a familiar sight in those decks. On average it shows up 1.0 times in the decks that take it.

It performs best next to Tremble — together they post a +20.0% swing in win rate. It also has strong chemistry with the relic Regal Pillow, which moves its win rate by +46.7%. At 1 energy, it’s upgraded in 30.0% of runs and usually joins the deck around floor 13.

Upgraded, it gains +4 Damage, which is why so many decks invest a rest-site upgrade in it. That’s 2 wins, 8 deaths, and 0 abandoned runs with it in the deck. The encounter that most often ends a run carrying it is The Insatiable Boss, which closes out 20.0% of its appearances. Read on for Breakthrough’s complete synergy, class, and threat breakdown to decide whether it earns a slot in your Ironclad run.

Best Cards to Pair with Breakthrough

Ranked by win-rate lift, Breakthrough performs best alongside Tremble (+20.0%), Molten Fist (+13.3%), and Thrash (+13.3%).

Tremble+20.0%5 runsMolten Fist+13.3%3 runsThrash+13.3%3 runsHeadbutt+5.0%4 runsAnger+5.0%4 runsBloodletting+5.0%4 runs

Based on small co-occurring samples — treat these as early signals, not final verdicts.

Breakthrough Win Rate by Class

Breakthrough is played across 2 classes, led by Ironclad (22.2%) and Silent (0.0%) by win rate.

The Ironclad22.2%9 runsThe Silent0.0%1 runs

Best Relics for Breakthrough

Breakthrough pairs best with the relics Regal Pillow (+46.7%), Bag of Preparation (+13.3%), and Anchor (+13.3%), ranked by win-rate lift.

Regal Pillow+46.7%3 runsBag of Preparation+13.3%3 runsAnchor+13.3%3 runsBurning Blood+2.2%9 runsVajra-20.0%3 runsOrnamental Fan-20.0%3 runs

Based on small co-occurring samples — treat these as early signals, not final verdicts.

Breakthrough Card Details

Breakthrough is a common attack costing 1 energy; it’s upgraded in 30.0% of runs and usually picked up by floor 13.

Lose 1 HP. Deal 9 damage to ALL enemies.

Upgrade: +4 Damage

What Ends Runs with Breakthrough

Breakthrough’s most common run-enders are The Insatiable Boss (20.0%).

• The Insatiable Boss20.0% of runs

See Also

Compare Breakthrough with the rest of the best Slay the Spire 2 cards, relics, and classes below.