Ironclad Strength Build: One-Shot Bosses with Demon Form + Limit Break

🏆 Build Guide · Updated May 19, 2026 · 8 min read · S-Tier

The Strength Build is the most consistent and powerful Ironclad archetype. By stacking massive amounts of Strength, you scale your damage exponentially — turning even basic attacks into boss-killing blows. With the right setup, you can one-shot Act 3 bosses with a single Heavy Blade dealing 200+ damage.

How It Works

The core loop is simple:

Generate Strength — Play cards like Demon Form or Inflame to gain Strength each turn.
Multiply Strength — Use Limit Break to double your Strength. Upgraded Limit Break doesn't exhaust, letting you double again and again.
Convert Strength to Damage — Heavy Blade scales 3× with Strength. Twin Strike hits twice for 2× scaling. Sword Boomerang hits 3-4 times for insane multi-hit synergy.

🔥 Core Engines

Engine 1 — Demon Form: The most reliable long-term scaling. Play it early in boss fights. Each turn you gain 2-3 Strength. After 5 turns, you have +10-15 Strength without spending any more energy. Safe, consistent, unstoppable.

Engine 2 — Spot Weakness: Fast, aggressive scaling. If the enemy is attacking, gain 3-4 Strength immediately. Much faster than Demon Form but requires the enemy to be attacking. Excellent in hallway fights and against aggressive elites.

Core Cards

Must-Have (S-Tier)

Demon Form — Your best scaling card. 3 cost is expensive, but once played, you win. Upgrade reduces cost to 2.
Limit Break — Doubles your Strength. Upgraded version does not exhaust, meaning you can play it every time you draw it. This is how you reach 50+ Strength.
Heavy Blade — Your finisher. Deals 14 + (Strength × 3) damage. At 20 Strength, that's 74 damage for 2 energy. At 50 Strength, 164 damage.
Offering — 0 energy: lose 6 HP, gain 2 energy, draw 3-5 cards. The best card in the game for finding your combo pieces.

Strong Support (A-Tier)

Spot Weakness — Gain 3-4 Strength if enemy intends to attack. Excellent early scaling.
Inflame — Simple, reliable: gain 2-3 Strength. Good early pickup.
Flex — Temporary Strength that's excellent with multi-hit attacks. Pairs with Limit Break if you can double it before it expires.
Headbutt — Crucial for recycling your key cards. Put Limit Break or Heavy Blade back on top of your deck.
Battle Trance — 0-cost draw 3-4 cards. Incredible for finding your combo pieces.

Defensive Options

Shrug It Off — Block + draw. Simple and effective.
Reaper — Attack ALL enemies and heal for unblocked damage. With high Strength, this full-heals you.
Impervious — 30-40 block for 2 energy. Stops any big attack.
Disarm — Against multi-hit bosses, this is better than block.

Best Relics

Vajra (S) — Start each combat with +1 Strength. Simple, effective, early-game powerhouse.
Snecko Eye (S) — +2 card draw every turn. Demon Form at cost 0-1? Yes please. Boss relic, requires commitment.
Brimstone (A) — +2 Strength per turn, but enemies also gain +1 Strength. High risk, but heavy blade out-scales them.
Girya (A) — Permanent +1 Strength per rest site use. Up to +3 total.
Dead Branch (A) — With Corruption, generates infinite cards. Not strength-specific but game-winning.

Run Strategy — Stage by Stage

Floors 1-8 (Early Act 1):
Take every attack card you see. Carnage, Hemokinesis, Anger, Pommel Strike — all good. Upgrade Bash at your first campfire. You need damage to kill Act 1 elites.
Floors 9-16 (Late Act 1):
Look for Spot Weakness and Inflame. If offered Demon Form, take it — but don't play it in hallway fights (too slow). Save it for bosses and elites. Prepare for your Act boss.
Floors 17-25 (Early Act 2):
This is where the build comes online. Take Limit Break whenever you see it. Add block cards: Shrug It Off, Disarm. Your deck should now have: 1-2 Strength generators, at least 1 Limit Break, and 2-3 strong attack cards.
Floors 26-33 (Late Act 2):
Refine. Remove Strikes aggressively. If you have Limit Break+ already, consider taking a second one. Headbutt becomes S-tier for cycling Limit Break. Avoid adding cards that don't directly support the strategy.
Floors 34-50 (Act 3):
Your deck should be a well-oiled machine. In boss fights: turn 1 play Demon Form (or Spot Weakness), followed by block cards while Strength grows. Around turn 4-5, start attacking. By turn 7, Heavy Blade one-shots anything.

💡 Pro Tip — Infinite Limit Break: With an upgraded Limit Break (does not exhaust) and a thin deck (under 20 cards after exhausting), you can play Limit Break multiple times per cycle. Headbutt lets you replay it immediately. This is how you reach 100+ Strength.

Matchup Notes

vs Gremlin Nob: Play Attacks only. Your high-damage attacks outrace him easily.
vs Slime Boss: You need AoE. Whirlwind with Strength is excellent. Split at the right HP threshold.
vs Guardian: He enters defense mode every other turn. Use those turns to play Demon Form. Attack during his vulnerable turns.
vs Collector: Kill the torch minions first — they deal the most damage.
vs Time Eater: Your worst matchup. Plan your 12-card limit. Use fewer, bigger attacks instead of multi-hits.

Also check: Ironclad Character Guide · Silent Poison Build