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’s a dependable, middle-of-the-pack option, landing at C tier in our rankings.

Across 85 recorded runs, decks running it win 31.2% of the time, comfortably clear of the 19.0% average, by 12.2%. It’s a more selective pick, turning up in just 2.2% of decks that could run it. Regent players keep it in 12.4% of their runs, so it’s a familiar sight in those decks. On average it shows up 1.3 times in the decks that take it.

It performs best next to Decisions, Decisions — together they post a +23.9% swing in win rate. It also has strong chemistry with the relic New Leaf, which moves its win rate by +22.9%. At 1 energy, it’s upgraded in 45.5% of runs and usually joins the deck around floor 14.

Upgraded, it gains +2 Forge, which is why so many decks invest a rest-site upgrade in it. That’s 24 wins, 53 deaths, and 8 abandoned runs with it in the deck. The encounter that most often ends a run carrying it is Decimillipede Elite, which closes out 7.1% 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 Decisions, Decisions (+23.9%), The Smith (+22.1%), and Void Form (+21.5%).

Decisions, Decisions+23.9%12 runsThe Smith+22.1%9 runsVoid Form+21.5%14 runsStardust+21.3%15 runsRadiate+19.4%10 runsComet+16.8%9 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 31.2% win rate across 85 runs.

The Regentappears in 12.4% of its runs (85 tracked)

Best Relics for Furnace

Furnace pairs best with the relics New Leaf (+22.9%), Pocketwatch (+19.7%), and Pendulum (+19.4%), ranked by win-rate lift.

New Leaf+22.9%6 runsPocketwatch+19.7%4 runsPendulum+19.4%10 runsAnchor+19.3%15 runsLantern+17.2%13 runsFencing Manual+17.0%11 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 45.5% of runs and usually picked up by floor 14.

At the start of your turn, Forge.

Upgrade: +2 Forge

What Ends Runs with Furnace

Furnace’s most common run-enders are Decimillipede Elite (7.1%), Skulking Colony Elite (4.7%), and Vantom Boss (4.7%).

• Decimillipede Elite7.1% of runs
• Skulking Colony Elite4.7% of runs
• Vantom Boss4.7% of runs
• Infested Prisms Elite3.5% of runs
• Knowledge Demon Boss3.5% of runs

See Also

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