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. Right now it’s a premium pick that sits at B tier — one of the better cards you can add to a deck this run.

Over 25 tracked runs its win rate sits at 26.1%, 13.5% ahead of the 12.6% all-deck baseline. It sees niche play, included in only 4.8% of eligible runs. Within Necrobinder runs it’s drafted 14.5% of the time, making it a regular part of that class’s decks. Decks that include it run about 1.2 copies on average.

Its standout pairing so far is Fetch, which lifts its win rate by +40.6% when the two share a deck. On the relic side, Unceasing Top is its standout companion, worth a +73.9% win-rate swing alongside it. It costs 2 energy, gets upgraded 50.0% of the time, and tends to be picked up near floor 14.

Upgrading the card adds +3 Summon to its stat line. Of the runs that drafted it, 6 ended in victory against 17 deaths and 2 abandons. Its most common run-ender is Decimillipede Elite, finishing 12.0% 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 (+40.6%), Reave (+40.6%), and Undeath (+40.6%), each shown with the win-rate lift it adds.

Fetch+40.6%7 runsReave+40.6%3 runsUndeath+40.6%3 runsEnfeebling Touch+40.6%4 runsCalcify+33.9%5 runsClumsy+31.1%7 runs

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

Necro Mastery Win Rate by Class

Exclusive to the Necrobinder, Necro Mastery posts a 26.1% win rate over 25 tracked runs.

The Necrobinderappears in 14.5% of its runs (25 tracked)

Best Relics for Necro Mastery

The relics that swing Necro Mastery’s win rate the most are Unceasing Top (+73.9%), Meal Ticket (+73.9%), and Oddly Smooth Stone (+73.9%), with each lift shown.

Unceasing Top+73.9%3 runsMeal Ticket+73.9%3 runsOddly Smooth Stone+73.9%3 runsStrike Dummy+57.2%6 runsSilver Crucible+40.6%3 runsBag of Marbles+40.6%3 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 50.0% of the time and tends to enter the deck around floor 14.

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 (12.0%), Infested Prisms Elite (8.0%), and Doormaker Boss (8.0%) — the share of its runs each accounts for is shown.

• Decimillipede Elite12.0% of runs
• Infested Prisms Elite8.0% of runs
• Doormaker Boss8.0% of runs
• Test Subject Boss8.0% of runs

See Also

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