Whistle Attack

Is Whistle good in Slay the Spire 2?

Whistle is an ancient Event attack in Slay the Spire 2. In combat it resolves as: Deal 33 damage. Stun the enemy. It ranks among the strongest cards its class can draft right now, earning a spot at B tier in our Slay the Spire 2 card tier list.

Across 92 recorded runs, decks running it win 54.4% of the time, comfortably clear of the 13.8% average, by 40.5%. It’s a more selective pick, turning up in just 0.4% of decks that could run it. Silent players keep it in 0.4% of their runs, so it’s a familiar sight in those decks. On average it shows up 1.1 times in the decks that take it.

It performs best next to Defend — together they post a +7.9% swing in win rate. It also has strong chemistry with the relic Juzu Bracelet, which moves its win rate by +13.9%. At 3 energy, it’s upgraded in 19.2% of runs and usually joins the deck around floor 33.

Upgraded, it gains +11 Damage, which is why so many decks invest a rest-site upgrade in it. That’s 50 wins, 42 deaths, and 0 abandoned runs with it in the deck. The encounter that most often ends a run carrying it is Aeonglass Boss, which closes out 12.0% of its appearances. Read on for Whistle’s complete synergy, class, and threat breakdown to decide whether it earns a slot in your Event run.

When to Pick Up Whistle

Whistle is strongest when it joins the deck in Act 3, where runs win 54.4% across 92 runs — one of 1 recorded pickup windows.

Win rate of runs by the act Whistle entered the deck. Acts that have not reached the sample floor show their run count only.

Best Cards to Pair with Whistle

Ranked by win-rate lift, Whistle performs best alongside Defend (+7.9%), Strike (+7.9%), and Survivor (+7.9%).

Defend+7.9%18 runsStrike+7.9%18 runsSurvivor+7.9%18 runsNeutralize+6.5%17 runsDefend+6.3%27 runsStrike+6.3%27 runs

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

Whistle Win Rate by Class

Whistle is played across 4 classes, led by Silent (66.7%), Ironclad (60.7%), and Necrobinder (50.0%) by win rate.

The Silent66.7%18 runsThe Ironclad60.7%28 runsThe Necrobinder50.0%20 runsThe Regent42.1%19 runs

Best Relics for Whistle

Whistle pairs best with the relics Juzu Bracelet (+13.9%), Happy Flower (+13.6%), and Bag of Marbles (+9.2%), ranked by win-rate lift.

Juzu Bracelet+13.9%17 runsHappy Flower+13.6%23 runsBag of Marbles+9.2%19 runsSparkling Rouge+8.9%16 runsPen Nib+8.9%16 runsRing of the Snake+7.4%15 runs

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

Whistle Card Details

Whistle is an ancient attack costing 3 energy; it’s upgraded in 19.2% of runs and usually picked up by floor 33.

Deal 33 damage. Stun the enemy.

Upgrade: +11 Damage

What Ends Runs with Whistle

Whistle’s most common run-enders are Aeonglass Boss (12.0%), Queen Boss (10.9%), and Test Subject Boss (9.8%).

• Aeonglass Boss12.0% of runs
• Queen Boss10.9% of runs
• Test Subject Boss9.8% of runs
• Knights Elite3.3% of runs
• Doormaker Boss2.2% of runs

See Also

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