Slay the Spire 2 Necrobinder — Class Guide, Osty & Starter Relic

The Necrobinder is a Spireborn lich out for revenge — and Slay the Spire 2's most fragile character at 66 Max HP. She fights by calling on her trusty left hand, Osty, a severed automaton hand that scuttles back into every battle whether she summons him or not. Playing her well means treating Osty less like a pet and more like a resource you are always either investing in or cashing out.

Necrobinder stats and starter relic

• Max HP: 66 — the lowest of all five classes
• Starting gold: 99
• Starter relic: Bound Phylactery — at the start of your turn, Summon 1
• How to unlock: complete a run with the Regent

Bound Phylactery has a quiet rider that defines the class: while you wear it, Osty reappears at the start of every turn with 1 HP if he isn't already on the board. Your left hand simply refuses to stay dead — which is exactly the energy the rest of her kit runs on.

Osty, the left hand

Osty is the Necrobinder's first and most important Summon:

• He occupies a board slot and fights for you, absorbing hits that would otherwise land on her 66 HP.
• Cards in her pool interact with him directly — buffing him, feeding him, or Sacrificing him for immediate value.
• Because Bound Phylactery resurrects him every turn, deaths on your side of the board are usually a scheduled part of the game plan, not a disaster.

How the Necrobinder plays

Her decks divide into three recurring plans:

1. Osty support — keep the hand alive and scaling; he becomes a wall that also swings.
2. Sacrifice engines — kill Osty (or other summons) on purpose, over and over, converting each death into cards, energy or damage.
3. Death-adjacent value — the broader undead toolkit: reanimating, draining, and abilities that care about things dying, enemy or otherwise.

What a good Necrobinder run looks like

Decide early whether Osty is your bodyguard or your battery. Support builds want health-scaling for the summon and defensive spells for the lich; sacrifice builds want the cheapest possible summon cycle and payoffs that trigger on exit. Her low HP means blocking is never optional — the class that cheats death most is the one that can least afford to experience it.

Build routes we recommend: the soul-drain engine, the ten-thousand-HP hand wall, the calamity burst deck and the nihil perpetual motion loop.

Ascension notes

Her Ascension ladder unlocks with an Act 3 boss kill. Ascension modifiers squeeze the narrowest health pool in the game hardest, so high-level Necrobinder runs lean even harder on Osty as a renewable shield.

Keep reading:

• All 5 Classes and Unlock Order
• Defect Class Guide
• Regent Class Guide