Slay the Spire 2 Co-op — Multiplayer Rules & Class Combos

Online co-op is Slay the Spire 2's headline feature — up to four players climbing one shared Spire, fighting the same enemies at the same time, and arguing over who gets the relic. The basics of hosting are covered in our multiplayer setup guide; this page is the playbook: the rules that actually shape a co-op run, the roles each player fills, and the class combos that carry lobbies.

How a co-op run actually works

• One shared map. All players visit every node together — the same fights, the same events, the same shops. Card and gold rewards are dealt out per player, so nobody starves.
• Relic rewards are shared. When a reward includes relics, each player picks one and the picks are divvied up. If two players select the same relic, the game settles it with an automatic game of Rock Paper Scissors. Yes, really.
• Downed players revive. If you die mid-fight, you come back at the next floor with 1 HP — as long as at least one teammate survived the fight. A total party wipe ends the run.
• Mend at rest sites. Rest sites gain a new co-op option: Mend, healing another player for 30% of their max HP. That means a party of four can patch two people per campfire.
• Potions are throwable at friends. Buff potions can be targeted at allies — carry one for your carry.
• Maps run shorter. Every act is one floor shorter in multiplayer, so bosses arrive on floor 16, 31 and 45. If someone takes the Golden Compass as their Act 2 Ancient relic, the whole party's Act 2 map becomes one long single path (+2 floors).
• Ascension is a lobby setting. The host picks the level, capped by the lowest Ascension anyone in the group has unlocked. Co-op Ascension progress is separate from your solo progress; winning a run raises the lobby's cap for everyone.

Party roles (who does what)

Role	Job	Best fit
Frontline	Body-block, apply Weak/Vulnerable, keep Block up so squishier classes don't eat hits	Ironclad, Necrobinder (Osty wall)
Damage carry	Delete elites and bosses before the fight outlasts your resources	Silent poison, Regent burst
Support	Draw-fixing, energy/Stars support, thrown potions, Mend duty	Defect, multiplayer-only Regent cards
caller	Route votes and boss prep — decide pathing out loud before the map vote	anyone with opinions

Roles are soft — every class in StS2 can deal damage — but parties that assign them before floor 1 simply die less.

Class combos that work

• Ironclad + anyone: Taunt and Tank redirect aggression while a carry scales. Ironclad's Vulnerable stacking (see the Dominate engine) also multiplies everyone's damage, not just his.
• Regent + Silent: Regent keeps the board busy with summons and Stars while Silent stacks poison on the boss. Regent's multiplayer-only cards (Plot, Constellation, Tutor, Largesse) pass draw and Stars around the lobby.
• Necrobinder + Defect: Osty soaks hits and pulls aggro while Defect sets up Frost/defense and chips from safety. Necrobinder's Capture Spirit toolkit also wants the extra body-count co-op provides.
• Double Silent: two poison stacks ramp faster than most bosses can scale — greedy, but it works.

Etiquette that keeps lobbies alive

1. Decide the route together — the map vote is the loudest argument in co-op; settle pathing in chat before votes lock.
2. Call dibs on relics before the reward screen, not during it — saves you from RPS heartbreak.
3. Save Mend for the person walking into the boss, not the healthiest player.
4. Don't quit after dying — the 1 HP revive at the next floor makes early deaths cheap.

Keep reading:

• Multiplayer Setup — How to Host and Join
• Slay the Spire 2 Crossplay — Is Co-op Cross-Platform?
• Best Class Tier List (0.105 Patch)
• Multiplayer Disconnect Fixes