Boost Away•Skill

Is Boost Away good in Slay the Spire 2?

Boost Away is a common Defect skill in Slay the Spire 2. In combat it resolves as: Gain 6 Block. Add a Dazed into your Discard Pile. It currently underperforms most alternatives, sitting at D tier in our Slay the Spire 2 card rankings.

Across 126 recorded runs, decks running it win 28.3% of the time, comfortably clear of the 19.0% average, by 9.4%. It’s a more selective pick, turning up in just 3.3% of decks that could run it. Defect players keep it in 21.4% of their runs, so it’s a familiar sight in those decks. On average it shows up 1.4 times in the decks that take it.

It performs best next to Machine Learning — together they post a +23.0% swing in win rate. It also has strong chemistry with the relic Tiny Mailbox, which moves its win rate by +30.0%. At 0 energy, it’s upgraded in 18.6% of runs and usually joins the deck around floor 14.

Upgraded, it gains +3 Block, which is why so many decks invest a rest-site upgrade in it. That’s 32 wins, 81 deaths, and 13 abandoned runs with it in the deck. The encounter that most often ends a run carrying it is Knowledge Demon Boss, which closes out 7.9% of its appearances. Read on for Boost Away’s complete synergy, class, and threat breakdown to decide whether it earns a slot in your Defect run.

Best Cards to Pair with Boost Away

Ranked by win-rate lift, Boost Away performs best alongside Machine Learning (+23.0%), Signal Boost (+20.9%), and Trash to Treasure (+19.5%).

Machine Learning+23.0%18 runsSignal Boost+20.9%14 runsTrash to Treasure+19.5%26 runsModded+18.8%14 runsSupercritical+18.5%11 runsDecay+17.2%5 runs

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

Boost Away Win Rate by Class

Boost Away is played across 2 classes, led by Defect (28.3%) and Silent (0.0%) by win rate.

The Defect28.3%125 runsThe Silent0.0%1 runs

Best Relics for Boost Away

Boost Away pairs best with the relics Tiny Mailbox (+30.0%), Blood Vial (+21.2%), and Pendulum (+20.9%), ranked by win-rate lift.

Tiny Mailbox+30.0%12 runsBlood Vial+21.2%24 runsPendulum+20.9%15 runsInfused Core+20.8%11 runsTouch of Orobas+20.8%11 runsJoss Paper+20.6%6 runs

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

Boost Away Card Details

Boost Away is a common skill costing 0 energy; it’s upgraded in 18.6% of runs and usually picked up by floor 14.

Gain 6 Block. Add a Dazed into your Discard Pile.

Upgrade: +3 Block

What Ends Runs with Boost Away

Boost Away’s most common run-enders are Knowledge Demon Boss (7.9%), Queen Boss (7.1%), and The Insatiable Boss (4.0%).

• Knowledge Demon Boss7.9% of runs
• Queen Boss7.1% of runs
• The Insatiable Boss4.0% of runs
• Kaiser Crab Boss4.0% of runs
• Ovicopter Normal3.2% of runs

See Also

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