Slay the Spire Silent Poison Guide: Scaling Damage Without Dying
How poison works, which Silent cards and relics to pick, and how to take down every boss up to and including the Corrupt Heart.
Poison is the Silent's slowest weapon and her most dependable one. A stack of Poison ticks at the start of the enemy's turn, goes straight through Block, and only falls off by 1 each turn. Point enough of it at something with a huge health bar and that thing dies, armor or no armor. The catch is the waiting: you're squishy while the counter climbs, and a few fights actively mess with poison. Here's how to build it, what to grab, and how to handle the bosses that matter.
Core Poison Cards
First, the loop. At the start of the enemy's turn, it loses HP equal to its Poison stacks, then the count drops by 1. So 5 Poison is 5 damage now, 4 next turn, 3 the turn after. The damage ignores Block, and Strength does nothing for it since that only pumps Attack cards. Total damage from x stacks works out to x times (x plus 1) divided by 2, so 20 stacks is 210 damage on paper. Fights usually end before the tail of that plays out. The whole game is shoving the count up fast.
Quick warning: each Artifact charge blocks one poison application, and Sentries, Donu, Deca, and the Bronze Automaton all wear Artifact. Burn the charges with cheap debuffs like Weak first.
| Card | Cost | Rarity | Effect (base / upgraded) | | --- | --- | --- | --- | | Deadly Poison | 1 | Common | 5 Poison / 7 Poison | | Poisoned Stab | 1 | Common | 6 damage + 3 Poison / 8 damage + 4 Poison | | Bouncing Flask | 2 | Uncommon | 3 Poison to a random enemy 3 times / 4 times | | Crippling Cloud | 2 | Uncommon | 4 Poison + 2 Weak to ALL / 7 Poison + 2 Weak | | Noxious Fumes | 1 | Uncommon Power | 2 Poison per turn to ALL / 3 per turn | | Catalyst | 1 | Uncommon | Double Poison / Triple Poison | | Corpse Explosion | 2 | Rare | 6 Poison, corpse deals its max HP to ALL / 9 Poison | | Envenom | 2 / 1 | Rare Power | 1 Poison whenever an Attack deals unblocked damage |
The everyday stackers
Deadly Poison is the workhorse. One energy for 5 stacks (7 upgraded) is a clean deal, and it's a common, so it shows up early. Grab one or two and stop there, because copies compete with block cards for energy. Bouncing Flask costs 2 and throws 3 Poison at a random enemy three times. In a single-enemy fight that's a flat 9 stacks on one body, 12 once upgraded. Crippling Cloud is the group glue: 4 Poison and 2 Weak to everything for 2 energy, and the upgrade to 7 Poison is one of the best in the deck. Poisoned Stab is fine early but doesn't grow, so don't chase copies.
The engine and the payoff
Noxious Fumes is the engine. Pay 1 energy once, and every enemy takes 2 Poison at the start of each of your turns for the rest of the fight, no cards required. Over a 10-turn scrap that's 20 free stacks on everything. Upgraded it's 3 per turn, and copies stack, though Snecko Skull only adds its +1 once. One fight charges you for playing Powers; that's in the boss section.
Catalyst is the payoff. One energy doubles the target's current Poison, exhausts. Take 20 stacks to 40 and you've printed a pile of damage for one card. The upgrade triples instead: 20 becomes 60. Catalyst loves company. Burst makes your next Skill play twice, and Catalyst is a Skill, so a doubled Catalyst takes 20 to 80. Nightmare drops three copies of a chosen card into your next hand: three base Catalysts take 20 stacks to 160, and upgraded ones take it to 540.
Cleaning up group fights
Corpse Explosion tags an enemy with 6 Poison (9 upgraded) and, when that enemy dies, everything else takes damage equal to its max HP. The blast scales with the corpse, so tag the fattest body in the room. Against Donu and Deca, both 250 HP, killing either one with this card hits the survivor for 250. Envenom is the attack-deck version of poison: 2 energy (1 upgraded) for a power that adds 1 Poison every time an Attack deals unblocked damage. Multi-hit attacks rack it up. Dagger Spray hits everything twice, Riddle with Holes hits five times, and with Snecko Skull each hit adds 2 instead of 1.
Campfire upgrade order: Noxious Fumes, then Catalyst (triple is a different card), then Bouncing Flask.
Block and Draw Priorities
Poison needs turns, and turns mean getting hit. The Silent starts at 70 HP, the lowest of the four characters (66 on Ascension 14 and up), so a poison deck that skimps on defense dies mid-recipe. Roughly half your picks after the core poison package should be block and draw.
Block that earns its slot
Backflip is the MVP: 5 Block plus draw 2 for 1 energy, blocking and digging for Catalyst at the same time. Deflect is a free 4 Block, Cloak and Dagger gives 6 Block plus a Shiv, and Dash bundles 10 Block with 10 damage. Leg Sweep lands 2 Weak along with 11 Block, and Weak matters against big single hits like the Heart's 40-damage Echo.
Footwork is the long-game pick: +2 Dexterity (3 upgraded) makes every block card better forever, and poison fights run long. One or two copies is plenty. At the top end, Wraith Form (3 energy) gives 2 Intangible, dropping incoming attacks to 1 damage each, but it eats 1 Dexterity a turn, so it's an emergency button, not a plan.
Draw and energy
Acrobatics (draw 3, discard 1) and Prepared (0 cost, draw 1 discard 1) smooth hands cheaply. Calculated Gamble is 0 energy: toss your hand, draw that many fresh ones, a fine way to hunt for Catalyst. Adrenaline is the rare you're happiest to see: 0 cost, gain 1 energy (2 upgraded) and draw 2. It pays for the Catalyst turn by itself.
Deck shape and the rhythm of a fight
Poison cards duplicate worse than they look: a fourth Deadly Poison spends a pick and an energy doing what Fumes does for free. Four to six poison sources total is the sweet spot, with the rest going to block, draw, and a couple of real attacks so Artifact enemies don't stall you.
The rhythm of a normal fight: turns 1 and 2, stack poison and block. Middle turns, mostly block, refreshing poison as the counter runs low. When stacks are fat, cash in with Catalyst. A thin deck helps, since you want Catalyst to show up on the turn you need it, so cut Strikes at shops and events when you can.
Relics That Support Poison
The three poison relics
Snecko Skull is a common, Silent-only relic, which is great news because commons show up constantly: whenever you apply Poison, apply 1 more. Fumes ticks 3 per turn (4 upgraded), each Bouncing Flask bounce carries 4, and Envenom's per-hit poison effectively doubles. One quirk: with Catalyst the bonus lands after the doubling, so doubling 20 gives 41.
The Specimen is the rare, and it's a group-fight machine: whenever an enemy dies, its Poison moves to a random survivor. Kill a pack in order and the stacks snowball onto the last body standing. Two caveats: a transfer onto something with Artifact vanishes completely (the Sentries fight is exactly this trap), and poison transferred during the enemy's turn doesn't tick again that turn.
Twisted Funnel is the shop relic: 4 Poison on every enemy at the start of every combat, no card, no energy. A free head start that turns each hallway fight into a countdown. Costs shop gold, and it's usually worth it.
Staying alive
Anchor starts each combat with 10 Block, covering your squishy setup turns. Blood Vial heals 2 per fight, Orichalcum gives 6 Block on turns you end without block, Oddly Smooth Stone is a permanent +1 Dexterity, and Thread and Needle stacks 4 Plated Armor into every combat. Gremlin Horn (1 energy and a card whenever an enemy dies) goes nuts alongside Corpse Explosion.
Boss relics
Energy relics from a boss chest are usually the pick: poison cards are cheap, but the Fumes-plus-block-plus-Catalyst turn is energy-hungry. Hovering Kite (the first discard each turn gives 1 energy) is nearly free energy for this deck, since Acrobatics and Prepared have you discarding anyway. Ring of the Serpent replaces Ring of the Snake and draws 1 extra card per turn, but you lose cards on turn one (6-card opener instead of 7) and only pull ahead on turn three. Wanting energy more than raw cards, poison decks usually pass.
Choosing Elite Fights
Elites drop the relics this deck runs on, so path toward them in Act 1 even at the cost of some HP. Know the matchups first, though, because two of them genuinely hate poison.
Act 1
Gremlin Nob (82-86 HP) is the scary one. He opens with Bellow, which gives him Enrage 2: every Skill you play hands him 2 Strength. Your whole poison kit is Skills, so every Deadly Poison is also a gift. His first turn is always Bellow, so that's a free setup turn: dump stacks, then stop feeding him. After that it's Bull Rush for 14 and Skull Bash for 6 plus 2 Vulnerable. If your deck is already Skill-heavy and slow, path elsewhere.
Lagavulin (109-111 HP) is the friendly one, with a wrinkle. It sleeps for three turns behind 8 Metallicize, which poison ignores since poison ignores Block. Free setup time. The wrinkle: poison damage wakes it early and burns its stunned turn, so either accept a shorter runway or hold off. Awake, it swings for 18, and every third turn Siphon Soul steals 1 Dexterity and 1 Strength.
The Sentries are three bodies of 38-42 HP, each carrying 1 Artifact, so your first poison application per Sentry bounces off. Burn the charges with cheap debuffs first. They alternate Bolt (2 Dazed into your discard) and Beam (9 damage). Kill an outer Sentry fast, because once your draw pile reshuffles, the Dazed come back and clog your hands.
Act 2
Book of Stabbing is a pure block check. Its Multi Stab starts at 6 damage a hit with a hit count that climbs every use, and Painful Stabs stuffs Wounds into your discard when it hits you. Nothing here punishes poison, so stack up, block big, and wait.
Gremlin Leader (140-148 HP) summons two gremlins at a time, up to three on the board, and Encourage hands everything +3 Strength. This is the Fumes fight: constant AoE poison melts the smalls while you focus the Leader. Corpse Explosion on a gremlin is a weak blast, so save it for the boss body.
Act 3
Giant Head pokes for 13 for four turns, then swings for 30, gaining 5 per swing up to 60. It carries Slow on itself, making it take more damage from your Attacks as you play cards. That does nothing for poison, and it doesn't need to: block the big hits, keep Fumes running, and the long fight favors you.
Reptomancer hits for 30 with Big Bite and spawns Daggers (20-25 HP each, up to four) that swing for 9 and then explode in your face for 25. You want AoE or the Daggers bury you. Corpse Explosion on a Dagger splashes about 25 everywhere, and Fumes taxes the whole board.
Nemesis is the worst poison elite in the game. Intangible every other turn reduces all damage and HP loss to 1, poison ticks included, while your stacks still burn down. Half your output evaporates. Either burst on the open turns or lean on block and eat the 45-damage Scythe. If your deck is poison-heavy, seriously consider the other path.
Preserved Insect, if you find it, cuts elite HP by 25%, and this deck gets full value from it. The one time to skip elites regardless: you're below roughly half health walking into an act boss. Dead pilots stack no poison.
Finishing Bosses and the Heart
Act 1
The Guardian (240 HP) flips into Defensive Mode after losing 30 HP in a mode, and that mode comes with Sharp Hide 3: every Attack you play costs you 3 damage. Poison decks barely play Attacks, so this is home turf, and poison damage counts toward the flip. Block the 32-damage Fierce Bash and you're fine.
Slime Boss (140 HP) loops Goop Spray (3 Slimed), Preparing (nothing), Slam (35). At half HP it splits into an Acid Slime and a Spike Slime sharing its remaining health, and about 70 damage by turn 3 forces that before a Slam lands. Poison ticks pushing it past half mid-fight trigger the split too, and Crippling Cloud plus Fumes clean up both halves after.
Hexaghost (250 HP) opens with Divider, scaled to your HP: your HP divided by 12, plus 1, times 6. At 70 HP that's 36, and it drops as you get hurt. After that it loops weak pokes and Burn spam until Inferno on turn 9. A race with a generous deadline, and early stacks win it.
Act 2
The Champ (420 HP) is a poison punching bag with one exception. Below half health he uses Anger, removing every debuff on him: all your poison, gone. He gains 6 Strength and follows with Execute (10 damage twice). Either bank a Catalyst to blow through the bottom half in a turn or two, or expect the reset and have Fumes rebuilding plus a fresh Catalyst ready. Face Slap and Taunt load you up with Weak, Vulnerable, and Frail, so bring block that doesn't need three cards a turn.
The Collector (282 HP) spawns Torch Heads (38-40 HP) and buffs everything with +3 Strength. Corpse Explosion a Torch Head and the splash nearly clears the minions. Mega Debuff lands on turn 4 with 3 Weak, 3 Vulnerable, and 3 Frail, so have your block plan set before then.
The Bronze Automaton (300 HP) shows up with Artifact 3, so three poison applications bounce before anything sticks. Chip the charges off with Weak from Neutralize or Sucker Punch. Its Bronze Orbs steal your highest-rarity card from your draw pile, often Catalyst, so killing orbs early is real card advantage. Block the 45-damage Hyper Beam or eat a very bad turn.
Act 3
The Awakened One (300 HP) is the poison puzzle box. Curiosity grants it 1 Strength every time you play a Power, and Noxious Fumes is a Power. It also regenerates 10 HP a turn. When it dies, Rebirth triggers: full heal, every debuff removed, your poison with it, though Curiosity goes away for phase 2. The Strength it banked from your Powers carries over, so don't spray Fumes in phase 1. Kill the first life fast with a modest stack, then commit the real poison to phase 2, where Dark Echo hits for 40.
Donu and Deca (250 HP each) both start with 2 Artifact, so burn two charges on each before poisoning. Donu buffs their Strength, Deca adds Block and Dazed. And this is the Corpse Explosion showcase: pop the Artifacts, tag one of them, and when it dies the other takes 250.
Time Eater (456 HP) is secretly a good matchup. Its Time Warp ends your turn on the spot every 12 cards you play and grants it Strength, and poison decks play two or three cards a turn. The landmine: below half HP it uses Haste once, removing all debuffs (poison included) and healing back to half. Same rule as the Champ: push through the threshold hard, or restart the clock after.
The Heart
Getting to act 4 takes three keys: the Ruby Key from a rest site (choose Recall instead of resting or smithing), the Sapphire Key from a chest (you take the key or the relic, not both), and the Emerald Key from a super elite, the one marked with a burning icon on the map. Act 4 itself is four rooms: rest site, shop, the Spire Shield and Spire Spear elite, then the Corrupt Heart.
The elite pair both carry an Artifact charge (two on Ascension 18), so strip those before poisoning. The Spear throws 10 damage three times and hands out Strength, and the Shield's Smash lands 34 every third turn.
Then the Heart itself: 750 HP. Three things define this fight. Beat of Death deals you 1 damage per card played (2 on Ascension 19), so card spam is out. Invincible caps its HP loss at 300 per turn (200 on Ascension 19), so there is no one-shot; you need at least three turns of real damage. And every third turn starting on turn 4 it buffs, in order: 2 Artifact, then +1 Beat of Death, then Painful Stabs, then +10 Strength, then +50 Strength around turn 16, which is death. That first buff matters most here: 2 Artifact stops your poison from sticking until you burn both charges with cheap debuffs like Neutralize's Weak.
The Heart opens with Debilitate, which piles 2 Vulnerable, Weak, and Frail on you plus one each of Burn, Dazed, Slimed, Void, and Wound into your draw pile. From there it trades Blood Shots (12 damage twice) and Echo (40). Poison fits this fight like a glove: steady per-turn damage that doesn't fight the Invincible cap, delivered while you spend the rest of your energy on block. Tungsten Rod turns Beat of Death's 1 damage into nothing. With Fumes ticking, 20 to 30 stacks banked, and a triple Catalyst cashed around turn 8 to 10, the Heart dies right on schedule, well before it grows the 50 Strength to say otherwise.