Slay the Spire Codexery

Poison

A creeping green decay that drains life with every passing breath.

Poison is a pervasive and insidious status effect found throughout the Spire, acting as a lingering curse that inflicts damage over time. Unlike immediate strikes or direct debuffs, Poison represents a slow, corrosive decay that weakens the target's vitality with every passing turn. It is a hallmark of the toxic flora and fauna native to the lower levels of the tower, often utilized by those who favor attrition warfare over brute force.

Type
Status Effect / Debuff
Primary Source
Toxic Plants, Slimes, and Corrupted Entities
Mechanic
Deals damage at the start of each turn until cured or duration expires
Common Counter
Purify, Detoxify, or specific healing abilities
Associated Character
The Ironclad (via Toxicity mechanics in fan interpretations) and The Watcher (via specific cards)
Visual Indicator
Greenish-yellow mist or slime coating the target

Lore & Background

Beyond natural infestations, Poison has been weaponized by various factions within the tower. Corrupted entities and rogue alchemists have learned to harness these volatile compounds, distilling them into potent agents that bypass traditional defenses. The effect is terrifyingly patient; it does not roar like fire or strike like lightning, but rather whispers of doom as the victim's health dwindles turn by turn. To be poisoned in the Spire is to fight a battle on two fronts: against one's immediate foes and against the very air one breathes.

In Their Own Story

The climber wiped sweat from their brow, ignoring the slick, green slime dripping from the ceiling vines above. A momentary lapse in concentration allowed a thorned tendril to graze their cheek. There was no sharp pain, only a cold numbness that spread instantly through the jaw. As the next turn began, the world seemed to blur slightly at the edges, and a phantom ache pulsed in their chest—a silent reminder that the tower itself was now eating them alive from the inside out.

Reader's Guide

Poison functions as a persistent debuff that triggers damage automatically at the beginning of the affected character's turn. This mechanic forces players to prioritize removal or mitigation strategies, as the cumulative damage can quickly overwhelm even high-health builds if left unchecked.

In the world of the Spire, Poison is primarily wielded by enemies such as Slimes, Corrupt Hearts, and various plant-based monsters. However, certain cards allow heroes to inflict this status on their opponents, turning the enemy's own vitality against them. It is particularly effective against foes with high block or health pools, as it bypasses defensive barriers.

To counter Poison, adventurers must seek out purification effects found in specific relics, potions, or character abilities that cleanse negative statuses. Without a cure, the poison will continue to drain life until the target falls or the duration naturally expires after several turns.

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