Among the vast arsenal of Borderlands 4 Weapons, few guns draw as much attention and excitement as the Kaoson. This Legendary submachine gun blends explosive mechanics with high fire-rate lethality, giving it a unique and potent identity on the battlefield. It's highly prized not only for its raw damage potential but also for the way it interacts with certain class builds and elemental loadouts.

 

However, obtaining the Kaoson isn't as straightforward as looting a chest on your first playthrough - it requires progression, specific boss encounters, and sometimes a bit of patience with RNG (random number generation). This guide will walk you through everything you need to know, from unlock requirements to farming strategies and tips for maximizing your chances of getting the version you want.

 

What Makes the Kaoson Special?

Before we dive into how to get this weapon, it's worth understanding why you might want it in your loadout. The Kaoson is a Legendary SMG manufactured by Vladof in Borderlands 4. What sets it apart from typical submachine guns is its unusual ammunition and explosion behavior.

 

Instead of firing standard bullets, the Kaoson launches sticky gyrojets - projectiles that adhere to whatever they hit and detonate later, either on reload or when you switch firing modes. This means a single volley of shots can result in multiple simultaneous explosions for massive damage output, especially when optimized with high fire rate and explosion-boosting gear.

 

This "stack-then-detonate" mechanic makes the Kaoson particularly strong against bosses, shielded enemies, and targets where you can stick enough projectiles before triggering the explosions. That's why many players seek out multiple elemental versions (e.g., kinetic, incendiary, cryo, shock) to tailor their arsenal to specific combat scenarios.

 

Where the Kaoson Drops

In Borderlands 4, the Kaoson can drop in several ways, but not all methods are equally reliable. Here's how the game distributes this sought-after weapon:

 

1. Farm from Primordial Guardian Origo (Best Method)

The most reliable way to obtain the Kaoson is by farming Primordial Guardian Origo, a vault boss located in the Arch of Origo in the Terminus Range's The Low Leys area. This boss is one of the designated sources for Legendary guns like the Kaoson, meaning it has a dedicated drop pool that includes this SMG.

 

However, you cannot fight Origo right away. Before the Arch of Origo vault will spawn, you must first collect three Terminus Range Vault Key Fragments scattered across Terminus Range. Once all fragments are assembled, the vault appears and you can enter the boss arena.

 

After defeating Origo, you can immediately farm him again using Moxxi's Big Encore Machine, located just outside the boss arena. This lets you loop the fight quickly, maximizing your chances of getting a Kaoson drop (or the specific element/roll you're targeting).

 

2. World Drops (Very Rare)

Kaoson also exists as a world drop, meaning it can theoretically drop from almost any loot source in the game - red chests, vending machines, random world bosses, or even rare drops from non-vault bosses. However, these chances are extremely low compared to farming Primordial Guardian Origo, so this method is generally not recommended if you're specifically hunting for a Kaoson.

 

The world drop option is nice because it means you could stumble across the weapon while playing normally, but dedicated farming is far more efficient for most players.

 

Step-by-Step: Farming Kaoson from Origo

Here's a detailed walkthrough to help you get to Origo and begin farming the Kaoson effectively:

 

Step 1: Collect Vault Key Fragments

The first requirement is finding the three Terminus Range Vault Key Fragments. These are scattered around the Terminus Range region and must all be collected before the Arch of Origo appears on your map. Each fragment location is usually marked by a large search area, and once you find all three, the vault entrance will activate.

 

This is similar to other vault access mechanics in the Borderlands series, where hidden or semi-hidden collectibles unlock a boss encounter with valuable loot.

 

Step 2: Enter the Arch of Origo Vault

Once the vault is active, head inside. You'll fight through a series of waves and arena enemies before reaching Primordial Guardian Origo. Be prepared - this boss fight is a step up from standard enemies, though not excessively difficult if you come prepared with good gear and elemental counters.

 

Origo relies heavily on shield health bars, which means weapon types that strip shields quickly - such as shock or radiation - will help shorten the encounter. Since Origo primarily fights at range and employs flying movement, slower weapons like heavy rifles or melee builds are less effective.

 

Step 3: Defeat Origo and Loot the Drop

After defeating Origo, the loot drop screen will appear. Kaoson is one of the Legendary weapons in his loot pool, but not guaranteed every time. You'll often get other Legendaries first, so be prepared to replay the fight several times if you're chasing a specific variant.

 

Step 4: Use Moxxi's Big Encore Machine

Once you've cleared the vault and defeated Origo, immediately use the Moxxi's Big Encore Machine outside the arena to restart the encounter without needing to exit the area or travel far - this greatly speeds up farming runs. Pressing the machine lets you re-queue the Origo fight in seconds and try for another Kaoson drop.

 

The more runs you can do per hour, the better your odds of getting the version you want - and many players have reported spending dozens to hundreds of runs before getting god-roll versions with desirable stats. You can also buy Borderlands 4 Boost to help you farm.

 

Understanding the Kaoson's Unique Mechanics

The Kaoson's standout mechanic is its "sticky explosive" behavior. Each shot effectively acts like a sticky grenade - the projectile adheres to the target, and then detonates when you either reload or switch firing modes. This creates a sequence of explosions instead of a stream of conventional bullets, which can stack for very high burst damage.

 

Because of this:

It excels in boss fighting where sticking many charges before detonation yields massive damage.

 

High fire rate and fast reload can multiply its damage potential substantially.

 

Alt-fire often has tracking capabilities, helping shots stick to moving targets more reliably.

 

Tips for Efficient Farming

Since Kaoson drops are not guaranteed each run, efficiency matters:

 

Optimize run loops: Use the vault reset machine and minimize travel time to get the most Origo kills per hour.

 

Play at a difficulty that lets you kill Origo quickly: Some players stick with a difficulty level that balances speed and loot quality - typically one where Origo goes down in 30-60 seconds so you can churn many runs.

 

Watch for elemental variants: Kaoson can roll kinetic, fire, shock, or cryo elements (others may exist but are rarer per community experience), so plan to stop farming once you have a set that covers all your needs.

 

Consider builds that improve fire rate and explosion damage: Since the Kaoson's power comes from explosions, builds focusing on enhanced fire rate and splash modifiers can make your guarantee kills faster and support quicker farming.

 

Final Thoughts

The Kaoson SMG is one of the most memorable and powerful weapons you can obtain in Borderlands 4. Its explosive stick-and-detonate mechanic makes it a force of destruction in the right hands, especially against bosses and tougher enemies. While the world drop chances are slim, the most effective way to secure one - and farm for specific variants - is to repeatedly defeat Primordial Guardian Origo in the Arch of Origo vault, using the Vault Key Fragments to unlock it and Moxxi's Big Encore Machine to sustain rapid farming runs.

 

Persistence is key. Many players invest hours into farming for elemental rolls or optimal stats, but the payoff - a Legendary Kaoson with the right build synergy - is well worth the grind. Whether you like stacking explosions for massive boss damage or want a versatile weapon that remains useful through many levels, farming for a Kaoson should be on every serious Vault Hunter's checklist.