Characters

Necrobinder: keep Osty useful and time Doom

Understand two health bars, Summon and the delayed kill threshold.

Early Access · Main 0.107.1 baseline; Beta 0.111.0 changes marked · Updated 2026-09-12

The short answer

Block reduces attacks first, then Osty absorbs remaining attack damage before Necrobinder. Doom reaching an enemy’s HP usually still leaves one enemy turn to survive.

Before you start

  • Play Regent to unlock Necrobinder.
  • Distinguish attack damage from direct HP loss.

Read current and maximum HP separately

Summoning a living Osty increases both current and combat maximum HP. Summoning while he is dead revives him with the Summon amount. Unleash reads current HP; Sacrifice reads maximum HP. Ordinary Osty attacks need him alive.

Kingy example: an intended 14 damage meets 5 Block and Osty at 6 HP. The remaining attack is 9: Osty takes 6 and Necrobinder takes 3. This example excludes other modifiers and direct HP loss.

Sources for this section

Survive the final enemy action

Doom executes when the affected unit ends its turn at HP no greater than its Doom. Artifact can cancel an entire application. End of Days is an immediate-check exception.

If an enemy has 20 HP and 20 Doom, ordinary Doom has met the threshold, but you still need to survive its pending action. An additional ordinary Doom card may accomplish less than Block on that turn.

Sources for this section

Pick complementary roles

CardRole
BodyguardSummon support.
UnleashAttack that uses Osty’s current HP.
SacrificeConvert Osty’s maximum HP into defense, killing him.
ScourgeApply Doom to one target.
Negative PulseDefense and Doom against a group.
No EscapeIncrease pressure after Doom is already present.
Sources for this section

Your checklist

0 of 3 ready · Stored only while this page is open.

Research checked 2026-09-12. This is a source-based guide; Kingy has not independently play-tested these steps. Evidence and coverage.

Independent fan guide. Slay the Spire 2 belongs to Mega Crit. Illustration by Kingy; not game footage.