Core Observer Location & Loot in Borderlands 4

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How to Find Core Observer & the Blacklime Bunker in Borderlands 4

How to Beat Core Observer (& Legendary Drops) in Borderlands 4

The Core Observer is a pretty easy boss to farm, and one that drops an abundance of decent loot. Whether it's because the Core Observer is the target of the weekly Moxxi's Big Encore, or you simply want to see what this mechanical monster drops, we've got all your Borderlands 4 needs covered right here. Check below to find out where to find the Core Observer, how to access the Blacklime Bunker, and, of course, what Legendary loot drops players can expect from this boss, all right here!

How to Find Core Observer & the Blacklime Bunker in Borderlands 4

Blacklime Bunker Walkthrough

Players can find the Core Observer within the Blacklime Bunker, which is located within The Howl of the Fadefields. In order to actually access the Blacklime Bunker, players must first complete the "One Fell Swoop" Main Mission. After which, they can head to the Bunker (location above) and open the Bunker door with a Locust canister. Players can find the Locust canister by standing on a ledge and double-jumping over to the central platform with a tree. Here, players can find a Locust station that allows players to pull out a canister and throw it at the Bunker door to enter.

We've attached a video to show you how to get inside the Blacklime Bunker, and get through it to meet the Core Observer!

Once you're inside the Bunker, head north and take the first right available. Follow through on the right and then take the next left for a more open Bunker room. Once inside, head north again through an open door, and keep to the left. Keep heading west, where you'll want to crouch and walk through some water to squeeze between some low-hanging pipes to access the lower region of the Bunker. From this point, keep heading west for a cold swim, where taking the left path (South) will take you to the Vending Machines before the Core Observer boss fight. From here, you can pay either 40,000 Cash, or 100 Eridium to fight the Core Observer (Eridium is only if the Core Observer is the Moxxi's Big Encore for the week).

How to Beat Core Observer (& Legendary Drops) in Borderlands 4

All Loot Drops from the Core Observer Boss

Legendary	Type	Special Effect
Bully	Pistol	Defense Protocol - When Gun Shields are activated, launches an Attack Drone every 14s
Defibrillator	Repkit	Cardiac Shock - When Health goes below 20%, there is a 50% chance to replenish a Repkit Charge.
Divided Focus	Assault Rifle	Conquerer - Fires bouncing Projectiles that pierce enemies

The Core Observer boss is a large Seeker drone that will shoot you with Shock bullets, which will make your shields drain faster. These bullets have a slower connection time, so just stay on the move and evade the boss's fire. The Core Observer has a Shield health bar, then an Armor health bar, and then a final Shield health bar. As such, we recommend Shock and Cryo weapons, as these are super effective against.

The only attacks players need to be mindful of outside of the Core Observer's central guns are the cluster of grenades that it can shoot at you. These can be shot while in the air to detonate them before they impact you. When it comes to farming, all weapons provided are fairly okay, so it's your preference what you farm based on your build.

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Action

Adventure

RPG

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OpenCritic Reviews: Top Critic Avg: 82 /100 Critics Rec: 88%

Released: September 12, 2025
ESRB: Mature 17+ / Blood and Gore, Intense Violence, Sexual Themes, Strong Language, In-Game Purchases, Users Interact
Developer(s): Gearbox Software
Publisher(s): 2K