Should I upgrade Deadly Poison in Slay the Spire 2?

Compare the upgraded text: Apply 7 Poison.. If the upgrade lowers cost, adds damage/block, or enables a combo piece, it is usually high priority.

What builds use Deadly Poison?

Deadly Poison appears in 1 tracked build: Venom Cascade (S-tier, core card).

What character uses Deadly Poison?

Deadly Poison is tagged as a Silent card. See the Silent build hub for archetypes that care about it.

Updated for Data 2026-03-17Early Access — numbers may shift with patches.

Deadly Poison

Silent · Skill · Common · 1 cost

Base

Upgraded

Card text

Apply 5 Poison.

Deadly Poison+

Apply 7 Poison.

Builds that use Deadly Poison

Archetypes that draft this card in real runs, with the role it plays.

SVenom CascadeSilent · Core card

Keywords

Poison

Build context

See the Silent build hub for archetypes that feature this card in real runs.

Related cards

Deadly Poison FAQ

Should I upgrade Deadly Poison in Slay the Spire 2?: Compare the upgraded text: Apply 7 Poison.. If the upgrade lowers cost, adds damage/block, or enables a combo piece, it is usually high priority.
What builds use Deadly Poison?: Deadly Poison appears in 1 tracked build: Venom Cascade (S-tier, core card).
What character uses Deadly Poison?: Deadly Poison is tagged as a Silent card. See the Silent build hub for archetypes that care about it.

Patch history

SpireForge snapshots card text from Untapped exports dated 2026-03-17. When Mega Crit ships a balance patch, we re-run the scraper and refresh every affected URL—see /patches for the editorial log.