Necro Mastery•Power

Is Necro Mastery good in Slay the Spire 2?

In Slay the Spire 2, Necro Mastery is a rare power from the Necrobinder card pool. Its effect: Summon 5. Whenever Osty loses HP, ALL enemies lose that much HP as well. The data flags it as a weaker pick, settling at D tier — usually one to pass on unless your deck specifically wants it.

Over 71 tracked runs its win rate sits at 27.0%, 8.0% ahead of the 19.0% all-deck baseline. It sees niche play, included in only 1.9% of eligible runs. Within Necrobinder runs it’s drafted 8.4% of the time, making it a regular part of that class’s decks. Decks that include it run about 1.1 copies on average.

Its standout pairing so far is Fetch, which lifts its win rate by +21.8% when the two share a deck. On the relic side, Oddly Smooth Stone is its standout companion, worth a +26.9% win-rate swing alongside it. It costs 2 energy, gets upgraded 37.2% of the time, and tends to be picked up near floor 16.

Upgrading the card adds +3 Summon to its stat line. Of the runs that drafted it, 17 ended in victory against 46 deaths and 8 abandons. Its most common run-ender is Decimillipede Elite, finishing 8.5% of the runs it shows up in. See the synergies, class split, and threats below for the full picture of where Necro Mastery fits a Necrobinder deck.

Best Cards to Pair with Necro Mastery

Necro Mastery’s strongest card pairings so far are Fetch (+21.8%), Legion of Bone (+16.9%), and Reanimate (+14.4%), each shown with the win-rate lift it adds.

Fetch+21.8%16 runsLegion of Bone+16.9%3 runsReanimate+14.4%11 runsFinesse+13.7%4 runsHaunt+13.4%14 runsHang+12.2%3 runs

Based on small co-occurring samples — treat these as early signals, not final verdicts.

Necro Mastery Win Rate by Class

Of the 2 classes that draft Necro Mastery, it performs best with Necrobinder (27.4%) and Silent (0.0%).

The Necrobinder27.4%70 runsThe Silent0.0%1 runs

Best Relics for Necro Mastery

The relics that swing Necro Mastery’s win rate the most are Oddly Smooth Stone (+26.9%), Ice Cream (+20.9%), and Bellows (+20.9%), with each lift shown.

Oddly Smooth Stone+26.9%9 runsIce Cream+20.9%4 runsBellows+20.9%5 runsLead Paperweight+16.9%3 runsFunerary Mask+16.9%4 runsStrike Dummy+16.5%10 runs

Based on small co-occurring samples — treat these as early signals, not final verdicts.

Necro Mastery Card Details

A 2-energy rare power, Necro Mastery is upgraded 37.2% of the time and tends to enter the deck around floor 16.

Summon 5. Whenever Osty loses HP, ALL enemies lose that much HP as well.

Upgrade: +3 Summon

What Ends Runs with Necro Mastery

Runs holding Necro Mastery end most often against Decimillipede Elite (8.5%), Queen Boss (7.0%), and Test Subject Boss (5.6%) — the share of its runs each accounts for is shown.

• Decimillipede Elite8.5% of runs
• Queen Boss7.0% of runs
• Test Subject Boss5.6% of runs
• Entomancer Elite4.2% of runs
• Doormaker Boss4.2% of runs

See Also

Keep exploring Slay the Spire 2 tier lists and stats below.