For a series centred around legendary Vault Hunters, there’s a surprising lack of vault hunting going on. I’m baffled to say that Borderlands 4 finally changes this, tasking you with finding nine vault key fragments to open three unique vaults hidden across Kairos.
While some are easy enough to track down, others are a right pain and will have you searching every nook and cranny—even once you’ve unlocked the hint by completing nearby silos. Below, I’ll go over where to find each of the vault key fragments and their respective vaults.
Since unlocking the silos isn’t actually required to find the fragment they point towards, I’ll cut to the chase for you (aside from the few cases where it’s easier to reach the fragment using the silos’ lift).
Fadefields vault and fragment locations
The Fadefield is the first area you’ll have access to on Kairos, and it’s a good idea to unlock its vault early on. Here’s where you need to go:
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Coastal Bonescape vault key fragment:
This fragment is on a crate at the base of a tower on the island near the water in Stillshore, in the southwest corner of Coastal Bonescape. This is the first fragment you’re likely to run into after leaving the prologue and helping Claptrap set up shop in the Abandoned Post safehouse, as there’s a bounty contract that leads you to the area.
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The Howl vault key fragment:
This one’s on a pedestal in a small cave on the northeast side of The Launch Pad (but southwest of Ardor’s Bounty). There are odd-shaped pillars nearby, so it’s easy enough to spot if you’re heading north up the main road from the settlement.
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Idolator’s Noose vault key fragment:
Head inside Rosemary’s Reserve to the northeast of Idolator’s Noose until you see the Propaganda Tower. Then, turn southeast and use your grapple to pull the loose vent blocking a hole in the wall, revealing a cosy nook where you’ll find the fragment on the Ripper’s corpse, as well as a Marcus bobblehead while you’re at it.
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Fadefields vault location:
With all three Fadefield vault key fragments, you’re ready to find the Arch of Inceptus vault. This vault is on a cliff to the east of the Fadefields, but you’ll need to grapple up the cliff face and clear the mangler nest first, as this leads to the path up the hill. Completing this vault will reward you with faster glide pack regeneration.
The Fadefields vault boss is the Primordial Guardian Inceptus, and there are a few things to be on the lookout for:
- You can grapple the boss to create pustules that you can shoot for critical damage.
- Inceptus can leap at you, spit corrosive blobs, and whip you with its tail, all of which require you to dodge to the side to avoid.
- Inceptus can also spin its tails around, so you’ll have to jump over this attack.
- For its most deadly attack, Inceptus will rise to the ceiling and cocoon itself, covering the floor with toxins and raining explosives. You’ll need to grapple around the arena to stay in the air, while shooting the weak spots at the top of the cocoon.
Carcadia Burn vault and fragment locations
Carcadia Burn is one of the two regions you can visit once you’ve progressed through the early hours of the main campaign, and it’s the area most players (myself included) have gone to next after the Fadefields. Here’s where you need to go to unlock its vault:
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Lopside vault key fragment:
The first fragment is lodged between two tables on top of the One Pumper gas station on the western edge of the Lopside region, just south of the Makeshift Chalet safehouse. All you need to do is grapple up to the roof, and it’ll be right in front of you.
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Ruined Sumplands vault key fragment:
This fragment is on a pedestal surrounded by odd pillars near the water outside of Hull’s Handbasket in the north of Carcadia Burn, past the Judgement’s Lapse silo. Head down the hill to the water and it’ll be on your right.
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Tonnage Peel vault key fragment:
The final fragment is inside the Wreck of the Last Great Hope, far west of The Lowrise safehouse. Head down to the western coast and you’ll see a ‘tunnel’ of sorts made from the wreck of the ship. Go inside and you’ll soon see a hatch in the ground on your left, near a red light, that you can yank up with your grappling hook. Jump down into the cave and you’ll find the fragment on the pedestal.
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Carcadia Burn vault location:
With the three vault key fragments in hand, head to the sandy plain in the northwest corner of the Grindstone of the Worthy region, northern Carcadia Burn, to find the Arch of Radix. It’s not too far east of The Lowrise safehouse, or north of the Rustical Hurl silo. Completing this vault gives you reduced glide pack regeneration delay.
Carcadia Burn’s vault boss is the Primordial Guardian Radix, and there are a few things to be on the lookout for:
- Radix primarily deals shock damage, which is strong against shields (blue) but weak against armour shields (green).
- Its health bar is entirely armour, so make sure to bring a strong corrosive weapon, or cyro as a fallback.
- Radix can throw rocks at you and leap towards you, requiring you to dodge backwards or to the side to avoid them.
- For most of the fight, Radix will be surrounded by spinning rocks that are best avoided by simply fighting from a distance.
- The most annoying attack sees Radix rise into the air and summon a storm, creating damaging areas on the ground that you’ll need to avoid.
Terminus Range vault and fragment locations
While you can enter Terminus Range at the same time as you unlock Carcadia Burns, it seems most players have saved it until last. Despite that, its vault reward is actually more useful, so it’s not a bad idea to grab it second. Here’s where you need to go:
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Vestal Garrison vault key fragment:
The easiest fragment to grab first is inside the Vestal Garrison, which is directly east of the entrance to the region from Carcadia Burn, or just southwest of The Nightcap safehouse.
Head up the stairs and through the large door into the garrison, then immediately turn left and go through another door up a small staircase to find a command room. The fragment is on a crate under the large monitor as you enter.
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The Low Leys vault key fragment:
This fragment is in the centre of the L-shaped Low Leys region by The Pit point of interest, north of the Eureka Stane crawler activity, and just east of the entrance from Carcadia Burn.
On the road towards The Pit, look out for a group of houses on stilts and a curved tree with pink leaves hugging a cliff face. You can climb up the rocks behind the tree, then grapple up to a ledge, where you’ll find the fragment on a pedestal.
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Cuspid Climb vault key fragment:
The third fragment is in a cave in the centre of Cuspid Climb, best accessed directly from The Reliquary silo. Jump out of the window and use the balloon lift to reach an outcrop to the north, which has a lone tree sticking off the end and a group of trees near a cave entrance. Go inside the cave and climb up a few rocks to find the fragment on a pedestal.
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Terminus Range vault location:
Now you’ve grabbed all three of the vault key fragments in Terminus Range, it’s time to find its vault, the Arch of Origo, on the border between The Low Leys and Cuspid Climb.
Head north on the main road from the Heritage Opus safehouse, and shortly after crossing the bridge into The Low Leys, look to your left to see a ledge on the other side of a ravine. Jump across and into the cave behind the shrine. Completing this vault rewards you with a 50% glide pack cost reduction.
The Terminus Range vault boss is the Primordial Guardian Origo, and there are a few things you should look out for:
- Origo can swap between ice and fire damage. Cryo is strong against armour, while fire deals bonus damage against your health.
- On the other hand, Origo’s health is all shields, so you should prioritise using a shock weapon, or a radiation weapon as a fallback.
- Its weak spot is the crystals on its back, which also show which element the boss is currently attuned to.
- Origo has a slam attack and can breathe the current element it’s attuned to, and these are both best avoided by dodging to the side.
- Origo will occasionally fly, bombing the arena and performing strafing breath attacks. Most importantly, it can cover the arena in fire or ice, which requires you to grapple open fissures on the ground to hover in the air until this attack is over.
