Necrobinder
Slay the Spire 2 Necrobinder guide with builds, cards, and strategy.
"A Spireborn lich who seeks revenge. Calls upon her trusty left hand, Osty, in combat."
A Spireborn lich who seeks revenge. Calls upon her trusty left hand, [gold]Osty[/gold], in combat.
Quick Answer
Necrobinder is a Spireborn lich in Slay the Spire 2 with 66 HP who fights alongside her companion Osty. Key mechanics include Doom (lethal threshold debuff), Soul tokens, and Ethereal cards — high risk, high reward.
Starting Relic
At the start of your turn, Summon 1. Can be replaced by Phylactery Unbound.
Strengths & Weaknesses
✦ Strengths
- Excellent draw and pile manipulation via Souls
- Insane tank potential with Osty as a shield
- Doom creates unique instant-kill win conditions
- High card draw via Soul cycling engine
✧ Weaknesses
- Requires high synergy between cards to function
- Slower playstyle needs careful planning
- Doom is delayed damage — vulnerable during setup
- Complex to pilot effectively for new players
Recommended Builds
Doom Execution
Stack Doom on enemies until it exceeds their HP, triggering an instant kill at end of turn. Scourge provides 13 damage plus draw for 1 Energy, while Negative Pulse applies AoE Doom with Block. Death's Door is an excellent defensive card once you have enough Doom sources. Time's Up finishes high-HP bosses. The build requires reliable Block to survive while waiting for Doom to tick down.
Skill 
Skill 
Skill 
Attack 
Skill 
Whenever a non-Minion enemy dies to Doom, heal 3 HP.
Enemies with at least as much Doom as HP deal 50% less damage.
Osty Aggro
Grow and protect Osty through Summon effects, then unleash devastating Osty Attacks. Pull Aggro effectively provides 11 Block value while building Summon synergies. Rattle is a key multi-attack damage source with great combo potential. Fetch is a zero-cost attack that cycles itself, and Flatten becomes free once you have enough Osty attacks. Sic 'Em provides both damage and Summon scaling.
Attack 
Attack 
Attack 
Skill 
Attack Osty deals 12 damage.
This card costs 0 if Osty has attacked this turn.
Whenever Osty attacks, gain 2 Block.
Soul Cycle Engine
Flood the board with Soul tokens through Dirge and Capture Spirit, then convert them into damage via Haunt (enemies lose life per Soul played) and Soul Storm (damage scales with exhausted Souls). Souls provide massive card draw, making this the most consistent cycling build. Death March adds burst damage based on cards drawn per turn. Keep the deck small for maximum cycle speed.
Power 
Attack 
Skill 
Skill 
Attack 
Every 5 times you Exhaust a card, draw 1 card.
Ethereal Burst
Play Ethereal cards aggressively — they Exhaust if unplayed — to power up Pull from Below, which deals damage for each Ethereal card played that combat. Defile provides efficient early damage at 13 for 1 Energy. Veilpiercer makes the next Ethereal card you play cost 0. Banshee's Cry deals 33 AoE damage and gets cheaper with each Ethereal played. Spirit of Ash generates Block per Ethereal card for sustain.
Attack 
Attack 
Attack Deal 10 damage.
The next Ethereal card you play costs 0 .
Attack Deal 33 damage to ALL enemies.
Costs less for each Ethereal card played this combat.
Power Gameplay Guide
Core Mechanics
Osty (Companion System)
Necrobinder fights alongside Osty, a reanimated companion summoned by the Bound Phylactery relic at the start of each combat. Osty has its own HP pool and automatically absorbs attack damage aimed at the Necrobinder through the Die For You passive. Summon effects increase Osty's current and maximum HP. If Osty dies, any Summon effect revives it next turn at 1 HP. This creates a dual health bar system unique to Slay the Spire 2.
Doom (Lethal Threshold)
Doom is Necrobinder's signature debuff in Slay the Spire 2. When a creature's total Doom stacks meet or exceed its current HP, it is instantly killed at the end of its turn. Stack Doom through Scourge (13 Doom), Negative Pulse (7 Doom to all enemies), and No Escape (bonus Doom if already applied). Time's Up deals damage equal to an enemy's current Doom, often triggering the execution. This is a high-risk, high-reward race to lethal thresholds.
Soul Tokens
Souls are 0-cost token cards that draw 2 cards and Exhaust. They are Necrobinder's primary engine for deck cycling and velocity. Generate Souls through Grave Warden (Block + Soul), Severance (damage + Soul), Capture Spirit (enemy loses life + generates 3 Souls), and Dirge (X-cost mass Soul generation). Playing Souls fuels Haunt (enemies lose life per Soul played) and Soul Storm (damage scales with exhausted Souls).
Ethereal Cards
Ethereal cards Exhaust at end of turn if not played — use it or lose it. Necrobinder builds around this with Pull from Below, which deals damage per Ethereal card played that combat. Veilpiercer makes the next Ethereal card free. Spirit of Ash generates Block for each Ethereal card played. This aggressive mechanic rewards committing resources immediately rather than holding cards in reserve.
Osty Mechanics Deep Dive
Osty's HP persists between turns (unlike Block). Summon cards effectively grant permanent defensive value. If Osty dies, it revives at 1 HP on next Summon — losing all accumulated HP. Osty does NOT absorb status damage or life loss effects. Plan for enemies that bypass Osty's shield. Osty counts as its own unit — buffs and debuffs on Necrobinder don't transfer to Osty. However, Lethality affects Attack Cards specifically, so it DOES buff Osty Attacks. This interaction is key to the Squeeze build. Osty visually grows as its HP increases, providing a clear indicator of your defensive state.
Pro Tips
Osty absorbs attack damage but NOT status damage or life loss effects. Don't rely on Osty against enemies that deal non-attack damage like Soul Fysh.
Summon effects persist between turns (unlike Block). Investing in Osty's HP early pays dividends across the entire fight — think of Summon as permanent Block.
Bone Shards sacrifices Osty for 9 AoE damage + 9 Block. Excellent in Act 1, but anti-synergistic with Unleash/Squeeze builds that need Osty alive and healthy.
When playing Souls, always play them before Death March or Soul Storm. Souls draw cards and Exhaust, which is exactly what those finishers scale off.
Necrobinder rewards commitment to one archetype. Splitting between Doom, Osty, Souls, and Ethereal leaves you with four half-built engines that win nothing.
Mistakes to Avoid
Drafting flashy finishers before the engine can reliably fuel them. Squeeze without Osty Attacks, Pull from Below without Ethereal cards — the payoff needs the setup first.
Mixing too many packages together. Necrobinder has four distinct archetypes. Trying to run all four in one deck creates hands full of ingredients with no payoff.
Neglecting Block entirely because Osty absorbs damage. Osty can die, and status effects bypass it. You still need real Block cards.
Letting Osty die carelessly. When Osty revives it comes back at 1 HP, losing all your Summon investment. Protect your Osty HP pool.
Ignoring Friendship as a Power card in Osty builds. The -2 Strength penalty doesn't affect Osty Attacks — it's pure upside (+1 Energy/turn) for Osty-focused decks.
Co-op Multiplayer Role
In co-op, Necrobinder excels as a debuff-and-control specialist. Doom stacking provides a unique lethal threshold that no other character can replicate — coordinate with your partner to soften enemies to the Doom execution range. Osty acts as an additional damage sponge for the team. Soul cycling gives Necrobinder exceptional consistency, making her a reliable partner. Pairs well with Ironclad (raw damage while Necrobinder controls) or Silent (double debuff layering for devastating enemy suppression).
Video Guide
10 Easy TIPS For NECROBINDER BUILDS in SLAY THE SPIRE 2
Necrobinder Database
Frequently Asked Questions
How do I unlock Necrobinder in Slay the Spire 2?
Play a run as the Regent (win or lose). Necrobinder unlocks after your Regent run completes.
What is the best Necrobinder build in Slay the Spire 2?
The Doom Execution build is the most distinctive, killing enemies instantly when Doom exceeds their HP. The Osty Squeeze build has the highest raw damage ceiling. Soul Cycle is the most consistent for deck cycling. Choose based on what the run offers.
How does Doom work in Slay the Spire 2?
Doom is a debuff that accumulates stacks. When an enemy's total Doom meets or exceeds their current HP at the end of their turn, they are instantly killed regardless of remaining HP. Stack it with Scourge, Negative Pulse, and No Escape.
Can Osty die permanently?
No. If Osty's HP reaches 0, it dies temporarily but can be revived by any Summon effect on your next turn. It returns at 1 HP, losing any accumulated HP. The Bound Phylactery relic also Summons 1 at the start of each turn.
What are Souls in Slay the Spire 2?
Souls are 0-cost token cards that draw 2 cards and Exhaust. They're Necrobinder's primary deck cycling tool and fuel damage sources like Haunt (enemies lose life per Soul) and Soul Storm (damage scales with exhausted Souls).
Is Necrobinder good for beginners?
No. Necrobinder is the most mechanically complex character in Slay the Spire 2, requiring management of Osty, Doom, Souls, and Ethereal mechanics simultaneously. Start with Ironclad or Silent, then try Necrobinder once you're comfortable with core game systems.
