Slay the Spire 2 has 577 cards, and 199 of them carry a grade from S to D. The distribution is not a pyramid: 18 S, 50 A, 45 B, 64 C, 22 D. The largest group is C at 64, and the smallest is S at 18.
The most useful pattern in that data is not the letter — it is the cost. The S tier averages 1.28 energy and 15 of its 18 cards cost exactly 1. The D tier averages 2.23 energy. In this game, the cards that earn a slot tend to be the cheap ones.
What the grades look like
| Grade | Cards | Share of 199 | Average cost |
|---|---|---|---|
| S | 18 | 9.0% | 1.28 |
| A | 50 | 25.1% | 1.28 |
| B | 45 | 22.6% | 1.36 |
| C | 64 | 32.2% | 1.58 |
| D | 22 | 11.1% | 2.23 |
Cost climbs as the grade falls, and it climbs sharply at the bottom. D is the only tier averaging above 2 energy, and it contains the only 9-cost card in the graded set (Banshee’s Cry, 33 damage to all enemies).
That is the mechanical reason the if-then rules below work. A 1-cost card competes for one energy in a three-energy turn; a 4-cost card competes with your entire turn.
The S tier is a 1-cost tier
Fifteen of the eighteen S cards cost 1 energy. The other three are 2, 2 and 4.
| Card | Cost | Effect | Damage per energy |
|---|---|---|---|
| Crash Landing | 1 | 21 to ALL enemies, fill Hand with Debris | 21.0 |
| Break | 1 | 20 damage, apply 5 Vulnerable | 20.0 |
| Giant Rock | 1 | 16 damage | 16.0 |
| Hemokinesis | 1 | Lose 2 HP, deal 15 | 15.0 |
| Hyperbeam | 2 | 28 to ALL enemies, lose 3 Focus | 14.0 |
| Rip and Tear | 1 | 7 damage twice | 14.0 |
| Ultimate Strike | 1 | 14 damage | 14.0 |
| Bury | 4 | 52 damage | 13.0 |
| Defile | 1 | 13 damage | 13.0 |
| Impervious | 2 | Gain 30 Block | 15.0 Block per energy |
Two numbers stand out. Crash Landing converts 1 energy into 21 damage across every enemy, and Impervious converts 2 energy into 30 Block — 15 Block per energy, more than any other graded card.
The 4-cost outlier is Bury: 52 damage for 4 is only 13 per energy, below several 1-cost cards. It still grades S because 52 in one card ends fights that 13-damage cards cannot, but the per-energy rate is a reminder that the tier is about role, not just efficiency.
The eight Rare traps
Eight of the 22 D-tier cards are Rare. These are the picks that look like upgrades and are not.
| Card | Pool | Cost | Effect | Why it fails |
|---|---|---|---|---|
| Banshee’s Cry | Necrobinder | 9 | 33 to all enemies, costs less per Ethereal played | 9 energy for 33 |
| Meteor Strike | Defect | 5 | 24 damage, Channel 3 Plasma | 5 energy for 24 |
| Murder | Silent | 3 | 1 damage, +1 per card drawn this combat | Starts at 1 |
| Tear Asunder | Ironclad | 2 | 5 damage, extra hit per HP lost | Needs a long fight to pay |
| Fiend Fire | Ironclad | 2 | Exhaust Hand, 7 damage per card | Eats your whole hand |
| Flak Cannon | Defect | 2 | Exhaust Status cards, 8 damage each | Blank without Status |
| Knockdown | Colorless | 3 | 10 damage, enemy takes double from others | Multiplayer only |
| Genetic Algorithm | Defect | 1 | 1 Block, +3 permanently per play | 1 Block now |
The pattern is conditional value. Every one of these needs a specific board state to be worth its slot, and in a 20-card deck a card that is dead half the time is worse than a Strike that is always 6 damage.
The if-then rules
These are ordered. The first one that fits decides the pick.
- If your deck is under 12 cards, take the card. You need options before you can thin; at 12 cards you are still building the base.
- If you already hold 2–3 cards of your core mechanic, remove a basic Strike or Defend. A Strike is 6 damage for 1 energy; almost every graded card beats that rate.
- If your deck is 20 cards or more and the plan is complete, remove instead of take. At five cards a turn, a 20-card deck shows you a specific card once every 4 turns; a 30-card deck once every 6.
- If the offer is 1-cost and graded A or better, take it even at 20+ cards. 15 of 18 S cards and 40 of 50 A cards cost 1, so the dilution cost is the lowest it gets.
- If the offer is a 4+ cost card that is not S, skip it. The D tier averages 2.23 energy; the S tier averages 1.28. Expensive cards have to be exceptional to justify the turn they eat.
Remove targets by the numbers
| Card | Damage or Block | Cost | Replace it when |
|---|---|---|---|
| Strike | 6 damage | 1 | Any A-tier 1-cost attack (13–21 damage) |
| Defend | 5 Block | 1 | Any A-tier block card (11+ Block) |
| A D-tier Rare | varies | 2.23 avg | Always — it costs more and delivers less |
Basic Strikes and Defends are the only cards where removal is unambiguously correct. A 6-damage Strike is beaten by Defile (13 for 1) at more than double the rate, and a 5-Block Defend is beaten by Fight Through (13 for 1).
“Bury — 4 energy, deal 52 damage (63 upgraded).” — STS2 card data, slaythespire.wiki.gg
Why grade never replaces reading the card
The A tier is 46% Common (23 of 50). The D tier is 36.4% Rare (8 of 22). If you pick by colour of the border, you get both of those backwards.
Grade is a summary of how a card performs in a normal deck. It cannot know that your deck has 12 Ethereal cards, which is exactly the condition that turns Banshee’s Cry’s 9-cost text into something playable — or that you have no Status generation, which makes Flak Cannon a blank.
Use the grade to filter, then read the card against your deck. The filter is 199 cards wide; the decision is one card wide.
Where to go next
The cards database has every card with its cost, damage and upgrade, and the rarity system explains why a Rare border does not mean a better card. If you want to fix a card rather than cut it, the enchantments page covers the 22 modifiers, and deckbuilding basics covers the curve these rules assume. To see what the deck has to beat, the boss table lists every HP pool from 173 to 512.