Sometimes, finding a boss in Borderlands 4 is as simple as exploring a cave. Unlocking Leader Willem to farm for the coveted Rainbow Vomit Legendary Shotgun is a whole ordeal—but one that is more than worth your time. Just don’t expect it to be quick.
## How to Unlock the Leader Willem Boss Fight in Borderlands 4
To unlock Leader Willem and start farming the Rainbow Vomit Legendary Shotgun, you need to complete the Electi Faction questline. This questline begins with two simple tasks in the short **Enter the Electi** side missions, followed by three more substantial missions. Everything culminates in the fight against Leader Willem and his Order allies.
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### How to Complete Enter the Electi, Part 1
Start Part One of **Enter the Electi** by speaking to Leader Kassandra at Carcadia after defeating Callis. You’ll be tasked with going to a Creep nest in the western part of the settlement to grab some food. True to Borderlands fashion, the “food” in this quest is bullets—food for guns.
Once you collect the crates of bullets, return to Carcadia and drop them off to complete this mission.
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### How to Complete Enter the Electi, Part 2
For the second part of the quest chain, you’ll work with Leader Willem to place five system relays around the Carcadia settlement. The order in which you place them doesn’t matter, but you must install all five.
Here are the relay locations:
– **North side**: Near some chairs behind a railing, tucked into a small nook in the wall.
– **West side**: On some scaffolding a bit further west.
– **Western entrance**: Close to the western entrance to Carcadia, on a lower level to the right of the shop with the red sign; near bags of unused concrete.
– **Southern edge**: At the top of a staircase by a large red geometric design and a barbed wire fence.
– **North side (again)**: Near the westernmost entrance by the final pole of a large awning overlooking the Burn.
After placing the fifth and final relay, return to Willem for your reward.
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### How to Complete The Council Divided
Begin **The Council Divided** by returning to Levaine in the Leaders Chamber. Someone has stolen many of Carcadia’s weapons, and they need to be recovered fast.
Fast travel to the Judgements Lapse Order Silo and head southwest to the Ripper camp. You don’t need to fight the rippers; instead, jump to the ladder leading to the weapon crates and grab an Echo Log from inside one. To reach the crates, jump on the rusted outbuilding near them, then cross the ladder.
The stolen weapons have been moved to a base in the northeasternmost portion of the Burn, your next destination. (Don’t forget to stop at the bridge waypoint near the Ripper camp to progress the quest.)
Upon arrival, the weapons become less of a priority, and you’re redirected to destroy three ships. You’ll need three bombs to do this:
– One bomb is near a large, spherical building on the eastern edge of the base.
– The second is on an upper level in the northeastern part, underneath a massive tangle of pipes.
– The third bomb is at the western edge of the base, behind a loot grill and a wrecked engine.
Each ship requires you to place two bombs, located as follows:
1. **First ship**: Main engine and a command console on the third floor.
2. **Second ship** (furthest northeast): Side of a main feed pipe and on the rudder.
3. **Third ship**: Back of the engine nearest the rudder and on the side of the main feed pipe.
After planting all bombs, head back across the water and take the elevator beneath the objective marker to the detonation point. Once the ships explode, a miniboss named MeatMeat will appear—defeat him to collect another Echo Log.
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### How to Complete A Traitor Within
Back in the Leaders Chamber, Levaine informs you the settlement now needs real food. You’ll head about a kilometer west to hunt thresher eggs:
– Kill four threshers and collect their eggs manually.
– Collect three pangolin salivary glands.
– Clear out a group of Order goons.
Next, travel south to **Moxxi’s Bottoms Up** to drop off the food on the counter. After this, head further south to a boneyard filled with rippers—eliminate them.
Then, kill a few kratch in a nearby cave and use Levaine’s grapple drone to proceed through the caves. Eventually, you’ll reach a large arena where Leader Willem has set an ambush.
Clear all enemies, then head to the control room. Your task here is to line up sets of holographic triangles so you can shoot through them all at once. Do this four times to unlock Willem’s logs.
Return the data drive containing the logs to Levaine and listen to her dialogue to complete the mission.
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### How to Complete The Moles Gambit
The final mission in the Electi questline begins by having you find and destroy the same relays you installed back in **Enter the Electi, Part 2**.
After destroying them, you must gather parts for an EMP device located at a junk site north of Carcadia. Clear the rippers there to search safely.
The EMP parts are:
– **Main housing**: A large, spherical device in the eastern portion of the junkyard.
– **Detonator**: On the upper level near a pair of stacked doors.
– **Antenna**: Reachable by jumping from near a frost barrel through hanging cargo containers to the uppermost platform.
Next, head south near the Rustical Hurl Order Silo to an Order Convoy. Defeat the enemies and hack the terminal to discover the location of Willem’s synth factory far to the east.
Expect to face Order enemies near the factory’s entrance and inside, though you can ignore them and focus on reaching the EMP site.
At the center of the factory, assemble the EMP device and survive for 91 seconds against waves of enemies as it charges.
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### Facing Leader Willem
With the EMP ready, you can now confront Leader Willem. He has undergone extreme cybernetic enhancements and is supported by squads of Order troops.
Defeat him repeatedly to farm the **Rainbow Vomit Legendary Shotgun**. As with any boss drop, there’s no guarantee you’ll get the item on every kill, but it’s definitely worth the effort.