The Primordial Guardians are among the toughest optional encounters in Borderlands 4. Hidden within the Primordial Vaults of Kairos, these massive bosses guard some of the best loot in the game, from devastating weapons to powerful class mods. Each Guardian requires players to first locate three Vault Key Fragments in their region before the vault opens, so preparation is essential. Once inside, you’ll battle through waves of enemies before facing the Guardian itself.
To enter a Primordial Vault, you must:
- Collect three Vault Key Fragments scattered across the region.
- Use the Order Silo to activate the vault entrance.
- Clear several enemy waves before the Guardian appears.
These fights are not locked behind endgame levels—you can attempt them as soon as you’ve collected the fragments. However, their respawn cost is higher than standard bosses, requiring a hefty cash payment at Moxxi’s Big Encore Machine to re-farm them.
Bring a balanced loadout with Shock, Incendiary, and Corrosive weapons to adapt to each Guardian’s shifting defenses.
Primordial Guardian Inceptus – Fadefields Vault
Location: Arch of Inceptus, Dissected Plateau, Fadefields
Health Bars: Shield → Flesh
Elemental Weaknesses: Shock (Shield) and Incendiary (Flesh)
Inceptus behaves like a predatory beast, attacking with its tail, spitting corrosive acid, and occasionally cocooning itself on the ceiling while flooding the arena with acid. Grapple points allow you to expose green weak spots on its cocoon or body, enabling critical damage.
Key Attacks
- Tail Stab / Sweep / Smash – Fast tail strikes that launch or knock back players.
- Homing Spores – Explosive spores that can be shot down mid-air.
- Cocoon Phase – Inceptus shields itself, filling the floor with acid; grapple points are essential for survival.
Legendary Drops
- Lucky Clover (Pistol)
- Husky Friend (Shotgun)
- Extra Medium (Shield)
- Ravenfire (Heavy Weapon)
- Firey Elementalist (Forgeknight Class Mod)
- Rewarding Filantropo (Exo-Soldier Class Mod)
- Electric Avatar (Siren Class Mod)
Primordial Guardian Origo – Terminus Range Vault
Location: Arch of Origo, The Low Leys, Terminus Range
Health Bars: Shield → Shield
Elemental Weakness: Shock
Origo is a flying Guardian, constantly switching between Cryo and Incendiary modes. Its aerial style makes melee builds difficult to use here. Origo dive bombs, unleashes ice spikes or fire bursts, and fires devastating elemental beams. Positioning and dashes are crucial to avoid falling off the arena.
Key Attacks
- Dive Bomb – Origo ascends, then slams down with splash damage.
- Ice Spikes / Fire Burst – Elemental barrages depending on its current mode.
- Elemental Beam – A powerful Cryo or Incendiary beam.
- Roar & Slams – Area-of-effect attacks requiring double jumps or geysers to evade.
Legendary Drops
- Kaoson (SMG)
- Watts 4 Diner (Shield)
- Bottled Lightning (Heavy Weapon)
- Kindred Spirits (Siren Class Mod)
- Driver (Harlowe Class Mod)
- Shatterweight (Amon Class Mod)
- Buster (Rafa Class Mod)
Primordial Guardian Radix – Carcadia Burn Vault
Location: Carcadia Burn
Health Bars: Shield → Armor → Armor
Elemental Weaknesses: Shock (Shield), Corrosive or Cryo (Armor)
Radix is the bulkiest and arguably the deadliest of the three Guardians. Surrounded by a rotating shield of Shock-charged rocks, Radix bombards players with shockwaves, lightning storms, and powerful ground dives. It also levitates mid-fight, summoning elemental pools and lightning bolts.
Key Attacks
- Rock Shield – Rotating rocks that absorb damage and punish melee attackers.
- Shockwave Punches – Ground slams creating expanding shockwaves.
- Shock Bombs – Area denial explosives.
- Levitation Phase – Pushes players back while dropping lightning strikes.
Legendary Drops
- Anarchy (Shotgun)
- Adrenaline Pump (Repkit)
- Teen Witch (Vex Class Mod)
- Scientist (Harlowe Class Mod)
- Forge Master (Amon Class Mod)
- Grenazerker (Rafa Class Mod)
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Quick Tips for Farming Primordial Guardians
- Always bring Shock weapons. All three Guardians start with Shield bars, making Shock your safest bet.
- Use grapple mechanics. Both Inceptus and Origo have weak points that require grappling or careful positioning.
- Stay mobile. Each Guardian has heavy splash attacks—double jumps, dashes, and glides are your lifeline.
- Farm for class mods. Every Guardian drops at least one mod for each Vault Hunter, making Vaults excellent for tailoring builds.
The Primordial Guardians represent Borderlands 4 at its best: chaotic fights, environmental hazards, and the promise of incredible loot. Inceptus rewards precision grappling, Origo tests your ability to stay airborne and react to elements, while Radix challenges your endurance and damage output. Whether you’re after a new Legendary weapon or that perfect class mod, these Vault bosses are absolutely worth the grind. Play Now!
