Slay the Spire: Defect A20H Strategy, Key Cards That Don’t Rely on Rares, Part 2: Sunder

Contents
- One card that goes a long way toward fixing the Defect’s weaknesses
- 32 damage when upgraded, and effectively free when it kills
- Against multiple enemies, use Sunder to cut down their numbers
- Ways to apply Vulnerable pay off big
- Use potions to play it twice in one turn
- It also works well with ways to increase your Energy
- Mainly an early-game card. Take it when you see it in Act 1
- Always take the first copy. You don’t need three
Image credit: © Mega Crit Games, LLC. Slay the Spire (PC/Steam version). This article uses a limited number of screenshots to explain gameplay strategy. The screenshots are from the Japanese version of the game.
Note: This article is about the original Slay the Spire and assumes Ascension 20 and an attempt to beat the Heart.
This continues my series on key Defect cards that don’t rely on rares. Last time, I covered Loop.
Part 2 covers the uncommon Attack, Sunder.
One card that goes a long way toward fixing the Defect’s weaknesses
The Defect is a character that struggles with killing enemies quickly and with fights against multiple enemies.
Sunder can solve those problems to a fair extent on its own. That’s why I want to call it a key card.
32 damage when upgraded, and effectively free when it kills

Its first strength is simply how much damage it deals. Upgraded, it deals 32 damage, and with Vulnerable on the enemy, that becomes 48.
And when Sunder kills an enemy, you get the Energy back, so it effectively costs 0. Firing off huge damage for practically nothing is an exceptional effect.
Once you have it, its upgrade priority is quite high.
Against multiple enemies, use Sunder to cut down their numbers
When there are several enemies, Sunder also makes it easy to reduce how many you’re facing, so it’s effective there too.
Among Act 2 Elites, it helps thin out the enemies in fights against the Gremlin Leader and the Slavers.
Ways to apply Vulnerable pay off big
Because it deals so much damage, it benefits greatly when Vulnerable is applied.
Starting with Beam Cell, it’s good to have ways to apply Vulnerable.
A Fire Potion is also very handy for bringing an enemy’s HP down to where Sunder can finish it off.
Use potions to play it twice in one turn
On top of that, with a Duplication Potion or Liquid Memories, you can play it twice in one turn, which is extremely strong.
You can even use these potions to force your way through Act 2 enemies, which the Defect tends to have a particularly hard time with.
It also works well with ways to increase your Energy
With only the starting 3 Energy, it can be a little awkward to use. Energy relics and cards make it easier to play.
Also, if its cost is changed by Snecko Eye or Enlightenment, the Energy you get back when it kills lets you increase your Energy. This can be very strong too, so it’s worth remembering.
Mainly an early-game card. Take it when you see it in Act 1
Sunder is basically an early-game card that’s strong in Acts 1 and 2. If you see it in Act 1, take it first and upgrade it.
From around the second half of Act 2, I start to hesitate over whether to take it. Against Act 3 bosses and the Heart, even Sunder’s damage gets harder to win with.
Still, it has uses in Act 3 as well:
- Fights against multiple enemies
- Elites
- Thinning out the Reptomancer’s minions
- Dealing a big hit to the Giant Head
If your deck doesn’t have enough answers for these, it’s a good idea to take it.
Always take the first copy. You don’t need three
In the early game, I always take the first copy. Two copies or so is fine, but I get the sense you don’t need three.
I hope this helps!


