Borderlands 4’s Bio-Bulkhead is one of the first bosses you fight in the game and the grappling hook is fundamental to get to the boss. Unlike anything you have faced so far in the game, Bio-Bulkhead won’t be beaten by simply shooting everything you have at them.
In our Borderlands 4 guide, we explain how to defeat Bio-Bulkhead, along with the rewards you receive from this fight.
Bio-Bulkhead location in Borderlands 4
You must defeat Bio-Bulkhead to progress in the campaign since it’s the final boss in the “One Fell Swoop” quest. The quest doesn’t end right after the fight, but you don’t have other bosses until the last moment of this mission.
To find Bio-Bulkhead, you need to invade Sol’s production facility in Synthetic Nave, which is located in the Dissected Plateau area (check our Borderlands 4 interactive map to find it). Once inside, help Zadra enter the lab. You will find a door that is protected by an impenetrable shield. To break it, you must use the air duct northwest of the room to access the lab.
Kill the enemies and activate the lever to get a sample of Locust. Now, you need to use your grappling hook to grab a capsule and throw it at the gate. Repeat the same process in the room where Zadra is.
Move forward to find a couple of vending machines before the boss arena.
Bio-Bulkhead’s moveset
In addition to Bio-Bulkhead, there will be a few androids who spawn sporadically around as well. Although these androids can be quite annoying, you should try to always keep one alive in case you are down in “Fight for Your Life” mode and need to kill an enemy to get back on your feet.
The main mechanic you should pay attention to involves Bio-Bulkhead’s shield. You can identify if the shield is up by checking Bio-Bulkhead’s health bar. Whenever it has lines crossing over the health bar, it means the boss won’t take any damage.
To temporarily destroy Bio-Bulkhead’s shield, you need to throw a Locust capsule at it. You can find some in the northern part of the lower level and the southern part of the upper level. There are no visual or audio cues indicating when the shield is coming back, but in our experience, the boss got it back up three times throughout the fight.
Throughout the fight, Bio-Bulkhead will keep chasing you, so you can actually just stay away from it and shoot while walking backward. You can use the stairs and pillars in the arena to create space between you and the boss while finding cover from the android’s shots as well.
Bio-Bulkhead can quickly reach you, so be ready to dash out of its attacks and keep a safe distance. The boss’s weak spot is its head, so aim for it to maximize your damage.
Below, you find a more detailed explanation of its moveset:
- Jump attack: Bio-Bulkhead jumps in place and creates a shock wave around it. The area where it lands becomes filled with electricity, which you’ll also want to avoid. If you are far enough from the boss, this attack is not a problem. However, if Bio-Bulkhead uses its jump attack after a gap-closer, then you should use your backpack to glide and dash out of it.
- Frontal shock wave: When hitting the ground with both hands, Bio-Bulkhead creates frontal shock waves. Since these waves travel a long distance from where the boss is, trying to run from them is not very effective. Do your best to glide and dash to the sides.
- Blue projectile: The boss slams its fists to create a blue projectile that flies forward following an S-shaped pattern. It’s tricky to avoid this one. sp try to time your dash for when it’s getting close. There are two variations of this attack, one with a single projectile and another with two.
- Gap closer: When you’re far from the boss, it may jump to where you are. While you can avoid this attack by running, the best strategy is to actually dash toward the direction it is coming from.
Bio-Bulkhead rewards
Defeating Bio-Bulkhead rewards you with experience points and guns, and like other boss fights, you can repeat it by paying a certain amount to Moxxi’s machine. When we fought it for the first time, at level 15, we earned 486 XP. At level 35 in the Ultimate Vault Hunter mode Rank 1, we got 2,080 experience points.
While the drops are random, we know that you may get the following legendary drops: Sho Kunai, Waterfall grenades, and Budget Deity pistol. After the fight, there’s also a red chest to open. What you get from it changes every time, but there’s a high chance of getting good loot from this type of chest.
Do you need more help with Borderlands 4? For those who are new to Kairos, check out our beginner’s guide before you get started and our best classes guide to find the right one for your playstyle.
If you want to have fun with your weapons, be sure to read our guide on how to get more SDU tokens. We know that traversing the immense map of Kairos is a challenge in itself, so you should prioritize unlocking a vehicle, as well as fast travel points. And if you’re already enjoying the endgame of Borderlands 4, don’t forget to check the weekly reset time for all current challenges.
