Amon Crucible builds in Borderlands 4: How the Freeze and Detonation setups work

Amon’s Crucible action skill is one of the most flexible kits in Borderlands 4. It freezes, detonates, and quietly turns Jakobs shotguns into boss erasers. The different Crucible builds that players gravitate toward all sit on the same core ideas: priming enemies with forge-axes, detonating for explosions and debuffs, and stacking gun and critical damage while staying tanky enough to stand in close.

What Crucible actually does for Amon

Crucible is Amon’s Cybernetics action skill. When activated, it summons Fire and Frost forge-axes that count as melee attacks and can be thrown to apply elements, Prime enemies, and set up Detonations. The tree wrapped around it adds three big levers:

• Priming and Detonating – Hitting with a forge-skill “Primes” an enemy. Detonating that target creates an explosion at their location and can trigger multiple damage and resource effects.
• Instant freeze with Frost Axes – With the Searing Cold augment in Cybernetics branch 3, Frost Axes can instantly freeze most non-boss targets. That lock-down makes lining up critical hits trivial.
• Gun debuffs for bossing – The Endless War augment increases an enemy’s gun damage taken per stack of Primed and spawns homing forge-axes on Detonation. It’s a direct damage multiplier in gun-focused setups.

On their own the axes are strong melee tools. Once they are tied into the rest of the Cybernetics, Vengeance, and Calamity trees, they become the engine for both single-target boss melts and room-wide detonations.

The Freeze Crucible (Frost Axe + Jakobs crit) build

The Freeze Crucible setup leans hardest into Searing Cold and critical hits. The basic loop is simple: freeze something with a Frost Axe, then shoot it in the weak spot with a giant Jakobs shotgun. Critical bullets ricochet into the room, and the Cybernetics tree rewards every crit with more damage and more Shock procs.

Key passives in Cybernetics for this style:

• Get The Lead Out – Flat reload speed that doubles after a Detonation. This keeps single-shot Jakobs guns feeling snappy and makes the whole build flow.
• Executioner – Critical hit damage that doubles for a short time after dealing melee damage. Crucible’s axes are melee, so every throw can set up a high-crit window.
• Bolt Action – Gives guns bonus Shock damage for a short time after each reload. Single-shot Jakobs shotguns constantly retrigger this, layering Shock on top of kinetic crits.
• Vital Organs – Kill skill that stacks gun critical hit chance. In dense fights it pushes crit uptime very high.
• Blast Furnace – Grants stacking increased damage whenever Amon or his forgedrones crit or Detonate. Detonations give multiple stacks, so the build snowballs quickly during chain kills.
• Lightning Rod – Adds a chance for Shock bolts to spawn on gun crits. This helps strip shields and feeds more status-based synergies.

From Vengeance, two passives fill obvious gaps:

• The Thrill – Regenerates missing health and ramps up when Amon takes or absorbs non-status damage. It’s cheap, passive sustain for a close-range build.
• Wrath of Nature – Boosts status application and Cryo effectiveness, and doubles those bonuses while the action skill is active. Frost Axes freeze more consistently and Cryo damage hits harder.

Calamity adds movement, shields, and a damage taken debuff:

• Impetus – Kill skill that increases shield regen and movement speed. It helps reposition between frozen targets and keeps shields topped off during chains.
• Heavy Plate – Pushes up maximum shield and overshield, giving breathing room in Ultimate Vault Hunter ranks.
• Gut Punch – Lets melee and ordnance apply Weakness, a status that makes enemies deal less damage and take more. Weakness benefits from status duration and counts as a status itself.

With Tempered Pyre and Twin Tempers online, axes also become autonomous damage and debuff delivery:

• Tempered Pyre – Every Forgeskill activation spawns an Incendiary Axe Forgedrone that orbits and slashes nearby enemies. Recasting while any forgedrones are active resets their durations.
• Twin Tempers – Adds a second forgedrone that deals Cryo melee damage but shortens all Tempered Pyre durations. The drones extend both Incendiary and Cryo coverage.

Once Gut Punch is learned, these forgedrones can apply Weakness as they swing. That means more enemies taking increased damage before the shotgun ever fires.

Recommended Freeze Crucible skill progression (to 50)

The Freeze build benefits from a specific ramp so that reloading and crits feel good early, while survivability and forgedrones come online later.

Throughout leveling, Crucible can start with the Endless War augment for early damage and then swap to Searing Cold at level 16. Endless War still has value for boss fights where the extra gun damage taken and homing forge-axes are worth giving up instant freezes.

Storm Surge capstone versus no-capstone leveling routes

High-end Freeze builds often path into Cybernetics branch 2 to pick up Storm Surge as a capstone. Storm Surge replaces Double-Edge with a twinned Shock Forgeblade that creates a persistent “Forgestorm” zone, dealing Shock damage over time and detonating any forge-axes attached to targets inside.

This is especially useful against shield-heavy enemies and bosses, where stripping shields and rolling detonations at the same time saves action skill charges and ammo. The trade-off is a long cooldown that does not mesh well with some leveling routes that rely on frequent Forgeskill use for immunity or Berserk uptime.

Some Crucible leveling builds intentionally skip all capstones. One common path takes only one point in Forged In Steel in Calamity for a 6-second damage immunity after activating a Forgeskill, then spreads the rest of the points through Bullet Storm and Berserk rather than reaching Storm Surge. That approach keeps Forgeskill and gun uptime high without being gated by a long-cooldown capstone.

The Detonation / forgedrone Crucible concept

Another Crucible archetype pushes further into explosions and splash damage rather than pure freeze-and-shotgun. It keeps Endless War as a center piece and turns Tempered Pyre forgedrones into both damage and resource engines.

The core loop:

• Activate Crucible to summon axes and spawn Tempered Pyre forgedrones.
• Use axes and drones to Prime as many enemies as possible.
• Detonate those targets to trigger chained explosions and spawn Endless War’s seeking forge-axes.
• Each Detonation and forgedrone crit ramps Blast Furnace stacks while certain passives restore shields and ordnance cooldowns.

This style spreads points differently across the three Cybernetics branches:

• In the “trunk”, Crucible, Tempered Pyre, Twin Tempers, Endless War, Executioner, Vital Organs, and Destruction Engine (a Forgeskill and detonation damage node) define the damage loop.
• Branch 3 adds Raging Inferno for a chance for action skill damage to crit and burn, Reactive Armor for shield/armor regen and ordnance cooldown on Detonation, and the Conflangarang capstone, which throws a large persistent axe and restores Forgeskill cooldown when it deals damage.
• Branch 2 still takes Blast Furnace, but swaps some survivability into Armor of Contempt for overshields whenever Amon deals action skill damage.
• Branch 1 gets at least a couple points in Cacophony to increase ordnance damage and Detonation radius. If survivability feels comfortable, more points can be shifted here to further amplify explosions.

The end result is a build that tries to keep a small army of forgedrones and looping Conflangarang blades on the field, constantly Priming enemies and refunding cooldowns through Detonations and capstone effects.

Weapons that actually feel good on Crucible Amon

Across both Freeze and Detonation styles, Amon wants guns with high per-shot damage and clean critical patterns. That’s partly because Executioner doubles crit damage after a melee hit, and partly because Blast Furnace rewards big, frequent crits.

• Hellwalker – A Jakobs shotgun with enormous base damage and a tight spread that rewards close-range crits. The single-shot reload behavior pairs perfectly with Get The Lead Out and Bolt Action.
• Hot Slugger – Another Jakobs shotgun with strong range for a shotgun and a kill skill that ramps damage after kills. It’s especially good during mobbing and early leveling.

Jakobs in general is the preferred manufacturer for these builds. Their crit-focused design, ricochet behavior, and fast reloads all line up with Cybernetics’ crit and reload passives. The builds skew heavily toward shotguns because they want to live in melee range anyway to throw axes and benefit from Executioner’s melee condition.

For leveling versions that lean on underbarrels and Repkits rather than legendaries:

• Spread Launcher underbarrels on Jakobs shotguns provide large single-target burst from the underbarrel shot, ideal for deleting bosses once Repkit amp is online.
• A 200% Damage Amp Repkit, especially an Order variant that comes with two charges and splash bonuses, can push this burst into one-shot territory.

Class mods, Enhancements, Specializations, and Firmware

Crucible builds use late-game systems to stretch their strengths rather than fix weaknesses.

• Class Mod – The Viking legendary class mod is a standout for Crucible because it grants two extra action skill charges. That means up to five axes to throw in quick succession, more Priming windows, and more chances to trigger Executioner and Searing Cold.
• Enhancements – A Jakobs Enhancement with Piercer (flat crit chance for Jakobs-licensed parts) or Sequencer (stacking bonus damage for consecutive crits) pushes crit-focused shotguns into true boss-melt territory. The ideal scenario is a Legendary Enhancement that rolls both.
• Specializations – The Bullet Train specialization from the Runner tree lets Amon hipfire while sprinting and scales gun damage with movement speed. From the Daredevil tree, Now With Caffeine reduces action skill cooldown whenever a Repkit is activated, I Am A Gun makes action skill damage benefit from gun damage increases, and A Honed Mind adds crit chance and crit damage to action skills themselves. Together they turn Crucible axes into something closer to a gun in how they scale.
• Firmware – Firmware sets such as Action Fist and Reel Big Fist stack flat melee and action skill damage. Since axes and some capstones count as melee and action skill hits, these sets directly increase both the initial axe throw and lingering action skill effects.

How to actually play a Freeze Crucible Amon

Step 1: Start every engagement by activating Crucible with the Searing Cold augment. Throw a Frost Axe at the highest-priority target in reach — Badasses or fast movers first. Most will freeze on impact, tougher enemies will at least slow.

Step 2: Close the distance on that frozen target and line up a point-blank critical hit with a Jakobs shotgun like Hellwalker or Hot Slugger. Because the target is frozen, it will not move during your aim, and Executioner’s melee trigger will already be active from the axe.

Step 3: Reload immediately after each shot to retrigger Bolt Action. The extra Shock damage helps chew through shields and keeps Blast Furnace and Lightning Rod procs flowing as you crit.

Step 4: Move between enemies using the movement speed from Impetus kill stacks, and let Tempered Pyre and Twin Tempers forgedrones swing on anything nearby. Their hits spread Incendiary and Cryo, apply Weakness when Gut Punch is learned, and keep Blast Furnace stacks refreshed between your own crits.

Step 5: On shielded bosses or dense packs, consider swapping to Endless War for a fight. Prime as many targets as possible with axes and drones, then chain Detonations to ramp up the gun damage taken debuff. Follow with underbarrel Spread Launchers or high-damage shotgun shots while that debuff is stacked.

While leveling, almost any gun can slot into this rhythm because the early tree investments boost gun and crit damage generically. The full Jakobs shotgun synergy only becomes mandatory once you lean into UVH ranks where everything hits harder and lives longer.

Crucible Amon ends up feeling less like a pure melee character and more like a shotgun duelist who happens to sling elemental axes and command a swarm of orbiting blades. Whether the focus is instant freezes plus Jakobs crits or endless Priming and Detonations from forgedrones, the same pillars keep showing up: keep Crucible active, keep Reload and crit passives rolling, and stand close enough that every pellet and axe swing lands where it matters.