Fasten•Power

Is Fasten good in Slay the Spire 2?

In Slay the Spire 2, Fasten is an uncommon power from the Colorless card pool. Its effect: Gain an additional Block from Defend cards. Right now it’s a premium pick that sits at S tier — one of the better cards you can add to a deck this run.

Over 56 tracked runs its win rate sits at 48.1%, 29.1% ahead of the 18.9% all-deck baseline. It sees niche play, included in only 1.5% of eligible runs. Within Necrobinder runs it’s drafted 1.9% of the time, making it a regular part of that class’s decks. Decks that include it run about 1.0 copies on average.

Its standout pairing so far is Countdown, which lifts its win rate by +21.4% when the two share a deck. On the relic side, Vajra is its standout companion, worth a +21.4% win-rate swing alongside it. It costs 1 energy, gets upgraded 34.5% of the time, and tends to be picked up near floor 18.

Of the runs that drafted it, 25 ended in victory against 27 deaths and 4 abandons. Its most common run-ender is Hunter Killer Normal, finishing 5.4% of the runs it shows up in. See the synergies, class split, and threats below for the full picture of where Fasten fits a Colorless deck.

Best Cards to Pair with Fasten

Fasten’s strongest card pairings so far are Countdown (+21.4%), Friendship (+19.5%), and Scourge (+19.3%), each shown with the win-rate lift it adds.

Countdown+21.4%7 runsFriendship+19.5%6 runsScourge+19.3%9 runsNo Escape+17.3%6 runsInvoke+17.3%7 runsHologram+17.3%6 runs

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

Fasten Win Rate by Class

Of the 5 classes that draft Fasten, it performs best with Necrobinder (57.1%), Defect (54.5%), and Ironclad (42.9%).

The Necrobinder57.1%16 runsThe Defect54.5%12 runsThe Ironclad42.9%8 runsThe Silent41.7%12 runsThe Regent37.5%8 runs

Best Relics for Fasten

The relics that swing Fasten’s win rate the most are Vajra (+21.4%), Regal Pillow (+20.6%), and Red Mask (+17.5%), with each lift shown.

Vajra+21.4%9 runsRegal Pillow+20.6%13 runsRed Mask+17.5%8 runsJoss Paper+17.3%5 runsBag of Marbles+16.0%10 runsLarge Capsule+14.8%4 runs

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

Fasten Card Details

A 1-energy uncommon power, Fasten is upgraded 34.5% of the time and tends to enter the deck around floor 18.

Gain an additional Block from Defend cards.

What Ends Runs with Fasten

Runs holding Fasten end most often against Hunter Killer Normal (5.4%), Entomancer Elite (5.4%), and Exoskeletons Normal (3.6%) — the share of its runs each accounts for is shown.

• Hunter Killer Normal5.4% of runs
• Entomancer Elite5.4% of runs
• Exoskeletons Normal3.6% of runs
• Decimillipede Elite3.6% of runs
• Kaiser Crab Boss3.6% of runs

See Also

Keep exploring Slay the Spire 2 tier lists and stats below.