Furnace•Power

Is Furnace good in Slay the Spire 2?

Furnace is an uncommon Regent power in Slay the Spire 2. In combat it resolves as: At the start of your turn, Forge. It currently underperforms most alternatives, sitting at D tier in our Slay the Spire 2 card rankings.

Across 21 recorded runs, decks running it win 14.3% of the time, comfortably clear of the 12.6% average, by 1.7%. It’s a more selective pick, turning up in just 4.0% of decks that could run it. Regent players keep it in 12.7% 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 Big Bang — together they post a +52.4% swing in win rate. It also has strong chemistry with the relic Bag of Marbles, which moves its win rate by +52.4%. At 1 energy, it’s upgraded in 39.1% of runs and usually joins the deck around floor 12.

Upgraded, it gains +2 Forge, which is why so many decks invest a rest-site upgrade in it. That’s 3 wins, 18 deaths, and 0 abandoned runs with it in the deck. The encounter that most often ends a run carrying it is Skulking Colony Elite, which closes out 14.3% of its appearances. Read on for Furnace’s complete synergy, class, and threat breakdown to decide whether it earns a slot in your Regent run.

Best Cards to Pair with Furnace

Ranked by win-rate lift, Furnace performs best alongside Big Bang (+52.4%), Particle Wall (+35.7%), and Shining Strike (+28.6%).

Big Bang+52.4%3 runsParticle Wall+35.7%4 runsShining Strike+28.6%7 runsStardust+25.7%5 runsNeutron Aegis+19.0%3 runsBeat into Shape+19.0%3 runs

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

Furnace Win Rate by Class

Furnace is drafted only by the Regent, where it holds a 14.3% win rate across 21 runs.

The Regentappears in 12.7% of its runs (21 tracked)

Best Relics for Furnace

Furnace pairs best with the relics Bag of Marbles (+52.4%), Whetstone (+19.0%), and Old Coin (+19.0%), ranked by win-rate lift.

Bag of Marbles+52.4%3 runsWhetstone+19.0%3 runsOld Coin+19.0%3 runsMiniature Cannon+19.0%3 runsLarge Capsule+2.4%6 runsDivine Right+0.7%20 runs

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

Furnace Card Details

Furnace is an uncommon power costing 1 energy; it’s upgraded in 39.1% of runs and usually picked up by floor 12.

At the start of your turn, Forge.

Upgrade: +2 Forge

What Ends Runs with Furnace

Furnace’s most common run-enders are Skulking Colony Elite (14.3%), Infested Prisms Elite (9.5%), and Vantom Boss (9.5%).

• Skulking Colony Elite14.3% of runs
• Infested Prisms Elite9.5% of runs
• Vantom Boss9.5% of runs
• Waterfall Giant Boss9.5% of runs
• Decimillipede Elite9.5% of runs

See Also

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