Updated for Data 2026-03-17Early Access — numbers may shift with patches.
Necro Mastery
Necrobinder · Power · Rare · 2 cost
Base
Upgraded
Card text
Summon 5. Whenever Osty loses HP, ALL enemies lose that much HP as well.
Necro Mastery+
Summon 8. Whenever Osty loses HP, ALL enemies lose that much HP as well.
Builds that use Necro Mastery
Archetypes that draft this card in real runs, with the role it plays.
Keywords
Build context
See the Necrobinder build hub for archetypes that feature this card in real runs.
Related cards
Necro Mastery FAQ
- Should I upgrade Necro Mastery in Slay the Spire 2?
- Compare the upgraded text: Summon 8. Whenever Osty loses HP, ALL enemies lose that much HP as well.. If the upgrade lowers cost, adds damage/block, or enables a combo piece, it is usually high priority.
- What builds use Necro Mastery?
- Necro Mastery appears in 2 tracked builds: Osty's Warband (A-tier, hero card), Soul Harvest (B-tier, flex pick).
- What character uses Necro Mastery?
- Necro Mastery is tagged as a Necrobinder card. See the Necrobinder 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.