There are plenty of bosses to fight in Borderlands 4, and while not all of them are special, the vast majority of them do have unique mechanics. The Bio Bulkhead, for example, may look like just a regular Order Bulkhead, but it is covered in a special bio-armor that makes it immune to all forms of damage.
This boss isn't particularly difficult, but regardless, here's a guide on how to beat the Bio Bulkhead in Borderlands 4 as well as info on what legendary loot you can target farm from it.
How to Farm Legendaries in Borderlands 4
Legendary items are extremely valuable in Borderlands 4, and if you're having trouble getting some, try these spots out.
How to Reach the Bio Bulkhead Boss in Borderlands 4
The Bio Bulkhead is the boss in One Fell Swoop, one of the main story missions in Borderlands 4. Here, you'll be storming an Order base in hopes of getting more info on Idolator Sol's bioweapon. The mission takes place in the Dissected Plateau mission, and in order to get to the Bio Bulkhead boss, you need to pass through the Order base again.
Make sure to go up the elevator once you reach the main hall.
If you're already finished with the One Fell Swoop mission, you can simply run past every enemy in the facility until you reach the boss room. For an easier time getting to the Bio Bulkhead boss, mark the location of its dedicated Encore machine, then call out ECHO-4. It will display a path that leads to the Encore machine.
How to Beat Bio Bulkhead in Borderlands 4
This boss introduces players to Locust Canisters, throwable objects that contain Sol's bioweapon. Bio Bulkhead is normally immune to all types of damage, but if you chuck a can of Locust at it, its armor will corrode, leaving it vulnerable to violence.
Locust Canisters will spawn in the dispensers by the pillars near the middle of the arena. If you miss your throw, you'll have to wait a bit for a new canister to spawn. Also, keep in mind that Locust Canisters will only destroy armor around its point of impact — if you hit the bulkhead from the front, its rear side will still be armored.
Bio Bulkhead Legendary Loot
Like most bosses in Borderlands 4, Bio Bulkhead can drop legendary items from the world loot pool as well as its own dedicated loot pool. This boss drops the following legendaries at a higher rate:
- Waterfall Grenade: A Vladof impact grenade that causes additional explosions when damaging targets.
- Sho Kunai Grenade: A Jakobs throwing knife that grants you a stacking movement speed bonus every time you hit enemies.
- Budget Deity Pistol: A Tediore pistol that produces Combo Orbs when thrown. Enemies damaged by Combo Orbs take damage and become marked with Atlas Target Lock.
The Budget Deity could be a good weapon if you want to build around the Atlas Tracker mechanic, but if not, then any other Tediore gun would be better. The Waterfall grenade is also quite good, but you'll want to have some sort of way to avoid blowing yourself up with it.
As cool as it sounds, the Sho Kunai has very little actual use cases. The movement speed buff isn't that strong, and unless it's paired with a build that uses movement speed, then this one is going to be a hard pass for many players.
Borderlands 4
- Released
- September 12, 2025
WHERE TO PLAY
- ESRB
- Mature 17+ / Blood and Gore, Intense Violence, Sexual Themes, Strong Language, In-Game Purchases, Users Interact
- Developer(s)
- Gearbox Software
- Publisher(s)
- 2K
- Engine
- Unreal Engine 5
- Multiplayer
- Online Co-Op, Online Multiplayer
- Cross-Platform Play
- Yes - all platforms
- Prequel(s)
- Borderlands 3, Borderlands 2, Borderlands
- Franchise
- Borderlands
- Number of Players
- 1-4 players
- Steam Deck Compatibility
- Unsupported
- PC Release Date
- September 12, 2025
- Xbox Series X|S Release Date
- September 12, 2025
- PS5 Release Date
- September 12, 2025
- Nintendo Switch 2 Release Date
- October 3, 2025
- Platform(s)
- PlayStation 5, Xbox Series X, Xbox Series S, Nintendo Switch 2, PC
- OpenCritic Rating
- Strong
- Local Co-Op Support
- Yes
- X|S Optimized
- Yes
