Deadly Poison•Skill

Is Deadly Poison good in Slay the Spire 2?

Deadly Poison is a common Silent skill in Slay the Spire 2. In combat it resolves as: Apply 5 Poison. 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 12.5% of the time, right in line with the typical deck. It’s a more selective pick, turning up in just 4.0% of decks that could run it. Silent players keep it in 20.2% of their runs, so it’s a familiar sight in those decks. On average it shows up 1.2 times in the decks that take it.

It performs best next to Flechettes — together they post a +37.5% swing in win rate. It also has strong chemistry with the relic Nunchaku, which moves its win rate by +37.5%. At 1 energy, it’s upgraded in 12.0% of runs and usually joins the deck around floor 10.

Upgraded, it gains +2 Poison, which is why so many decks invest a rest-site upgrade in it. That’s 2 wins, 14 deaths, and 5 abandoned runs with it in the deck. The encounter that most often ends a run carrying it is Knowledge Demon Boss, which closes out 9.5% of its appearances. Read on for Deadly Poison’s complete synergy, class, and threat breakdown to decide whether it earns a slot in your Silent run.

Best Cards to Pair with Deadly Poison

Ranked by win-rate lift, Deadly Poison performs best alongside Flechettes (+37.5%), Pounce (+37.5%), and Piercing Wail (+20.8%).

Flechettes+37.5%4 runsPounce+37.5%3 runsPiercing Wail+20.8%3 runsEscape Plan+20.8%3 runsAdrenaline+20.8%3 runsMirage+20.8%3 runs

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

Deadly Poison Win Rate by Class

Deadly Poison is drafted only by the Silent, where it holds a 12.5% win rate across 21 runs.

The Silentappears in 20.2% of its runs (21 tracked)

Best Relics for Deadly Poison

Deadly Poison pairs best with the relics Nunchaku (+37.5%), Red Mask (+37.5%), and Festive Popper (+20.8%), ranked by win-rate lift.

Nunchaku+37.5%4 runsRed Mask+37.5%3 runsFestive Popper+20.8%4 runsBlood Vial+20.8%3 runsBag of Preparation+20.8%3 runsOddly Smooth Stone+20.8%3 runs

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

Deadly Poison Card Details

Deadly Poison is a common skill costing 1 energy; it’s upgraded in 12.0% of runs and usually picked up by floor 10.

Apply 5 Poison.

Upgrade: +2 Poison

What Ends Runs with Deadly Poison

Deadly Poison’s most common run-enders are Knowledge Demon Boss (9.5%).

• Knowledge Demon Boss9.5% of runs

See Also

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