Should I upgrade Synthesis in Slay the Spire 2?

Compare the upgraded text: Deal 18 damage. The next Power you play costs 0 Energy.. If the upgrade lowers cost, adds damage/block, or enables a combo piece, it is usually high priority.

What builds use Synthesis?

Synthesis appears in 1 tracked build: Machine Mind (B-tier, core card).

What character uses Synthesis?

Synthesis is tagged as a Defect card. See the Defect build hub for archetypes that care about it.

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

Synthesis

Defect · Attack · Uncommon · 2 cost

Base

Upgraded

Card text

Deal 12 damage. The next Power you play costs 0 Energy.

Synthesis+

Deal 18 damage. The next Power you play costs 0 Energy.

Builds that use Synthesis

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

BMachine MindDefect · Core card

Build context

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

Related cards

Synthesis FAQ

Should I upgrade Synthesis in Slay the Spire 2?: Compare the upgraded text: Deal 18 damage. The next Power you play costs 0 Energy.. If the upgrade lowers cost, adds damage/block, or enables a combo piece, it is usually high priority.
What builds use Synthesis?: Synthesis appears in 1 tracked build: Machine Mind (B-tier, core card).
What character uses Synthesis?: Synthesis is tagged as a Defect card. See the Defect 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.