In Borderlands 4, you’ll encounter Bio-Bulkhead during the main quest. He carries a unique shield that makes him tricky to take down. Here’s how to beat him.
In the main quest “One Fell Swoop,” you’ll face off against a standout boss: Bio-Bulkhead. This fight introduces a special mechanic that rewards both timing and accuracy. Below, you’ll find details on his location, the fight phases, unique abilities, and possible drops.
Borderlands 4: Where to Find Bio-Bulkhead
You’ll encounter Bio-Bulkhead during the quest “One Fell Swoop” in a sealed-off lab area of the main story. The arena is a large circular room built specifically for this boss fight. To even reach it, you’ll first need to break down several doors using canisters filled with locust gas. This section also acts as practice – you’ll need those canisters for the fight itself.
The Fight Mechanics
Bio-Bulkhead is very different from typical bosses. His core mechanic revolves around a locust shield. While it’s active, he’s completely immune to damage, so spraying bullets won’t help.
The fight plays out in two phases:
- Shield Phase: Bio-Bulkhead is surrounded by a swarm shield that makes him invulnerable. This is when you need to use the locust canisters – special containers generated by a machine in the arena. Use your grappling hook to pull them out and throw them directly at him.
- Vulnerable Phase: Once a canister hits, it explodes and breaks the shield, leaving Bio-Bulkhead open to damage. This is your window to deal as much damage as possible before the shield regenerates.
Attack Patterns and Threats
Bio-Bulkhead is dangerous not just because of his shield but also due to his attacks. Two moves are especially important to watch out for:
- Ground Shockwaves: When he stomps, shockwaves spread across the ground. Keep your distance and jump at the right time – a double jump usually works.
- Leap Attacks: The mutated Bulkhead can cover huge distances and strike in melee. Stay mobile, keep your distance, and use the arena to move around. In co-op, split tasks: one player grabs the canister while the others get ready to shoot.
Smaller enemies will spawn throughout the fight. Leave a few alive if possible – taking them out can revive you if you get downed.
Bio-Bulkhead: Drops and Rewards
Defeating Bio-Bulkhead rewards you with the usual boss loot: XP, money, gear, and with some luck, unique weapons or mods that only he can drop. He’s a solid target for farming rare loot, so make sure to comb through the arena once the fight is over.
