Antewise

Flatten — Necrobinder Attack Card in Slay the Spire 2

Updated 17 Oct 2026 Source Slay the Spire 2 card data (spire-codex.com API), 577 cards retrieved 17 October 2026 By
Data status: The facts on this page were checked against the source named above. Game values can still shift with a patch, so re-check anything that looks off.
Flatten card art
Flatten

Osty deals 12 damage. This card costs 0 1 Energy if Osty has attacked this turn.

CharacterNecrobinder
TypeAttack
RarityCommon
Cost2 Energy
TargetAnyEnemy
Total damage12
Per Energy6.00 → 6.00 upgraded
TagsOstyAttack

Card text

Osty deals 12 damage. This card costs 0 1 Energy if Osty has attacked this turn.

Upgraded: Osty deals 16 damage. This card costs 0 1 Energy if Osty has attacked this turn.

Where it sits on the curve

Measured the same way as our efficiency tier list: total damage divided by Energy.

Flatten produces 6.00 per Energy at base . That ranks it 96 of 143 of the 143 attacks with a fixed cost. It sits in the top 34% on this measure.

The measure ignores everything that is not a number. Area damage, conditions and drawbacks are not priced in.

Other Necrobinder cards at 2 Energy

  • Deathbringer — Apply 21 Doom and 1 Weak to ALL enemies.
  • Delay — Gain 11 Block. Next turn, gain 1 Energy.
  • Eidolon — Exhaust your Hand. If 9 cards were Exhausted this way, gain 1 Intangible.
  • Forbidden Grimoire — At the end of combat, you may remove a card from your Deck.
  • High Five — Osty deals 11 damage and applies 2 Vulnerable to ALL enemies.
  • Legion of Bone — ALL players Summon 6.

Where to go next

All 577 cards — the full table, filterable by character. Efficiency tier list — every measurable card ranked.

Rarity system explains how often this card appears. Enchantments covers the modifiers that can change it.

Frequently asked questions

What does Flatten do in Slay the Spire 2?

Osty deals 12 damage. This card costs 0 1 Energy if Osty has attacked this turn.

What does upgrading Flatten change?

Osty deals 16 damage. This card costs 0 1 Energy if Osty has attacked this turn.

How much does Flatten cost?

2 Energy. It is a Common Attack card.

Is Flatten efficient for its cost?

It produces 6.00 damage per Energy, which ranks 96 of 143 among the attacks that can be measured this way.

More Slay the Spire 2 guides

Sources

Figures and item data on this site are read from the game’s own reference wiki before publishing. Where a value could not be confirmed there, the page says so instead of filling the gap.