Flat Kairoser: Borderlands 4 Flat Kairoser walkthrough

Borderlands 4 has its share of humorous side quests, including one dubbed Flat Kairoser. As should be easy to glean from the title, this side mission is a jab at the absurdity of Flat Earth mentality, but with a Kairos denizen instead. This quest is also a somewhat lengthy one, seeing players traipse all around the planet's snowy tundra to heed a conspiracy theorist's requests.

This guide has everything you need to know about the Flat Kairoser quest in Borderlands 4. Here are the details.

Also Read: Borderlands 4: All Stoneblood Forest collectibles

Borderlands 4 Flat Kairoser step-by-step guide

Flat Kairoser side mission location in Borderlands 4 (Image via 2K)

Quest Giver: Skeptical Sam
Location: Southern Terminus Range
Prerequisites: Finish the main mission "A Lot to Process"
Rewards: XP, Cash, Weapon (Uncommon to Epic), Vault Hunter Customization, ECHO-4 Customization, and Eridium

This side mission can be found upon unlocking the Terminus Range and is located just south of the Grey Havenage safehouse. You will meet an eccentric NPC named Skeptical Sam, and talking to him begins this quest. He is Kairos' version of a Flat Earther, and it is up to the Vault Hunter to prove him wrong.

Take the flattened Kairos model to begin the quest (Image via 2K)

Here is the full rundown of objectives:

Take Flat Kairos
Stomp dang globe
Follow Sam
Reach Shrine
Reach wrecked ship
Collect surveying equipment
Find suitable launch site
Place atmospheric surveyors
Activate surveyors
Find the balloons
Talk to Sam

How to complete the Flat Kairoser quest in Borderlands 4

Take the Kairos Globe and Stomp it

Flatten the Kairos globe model by slamming down on it (Image via 2K)

After talking to Skeptical Sam, he gives you a Flat Kairos model. Once that is done, he will ask the Vault Hunter to similarly flatten the Kairos globe sitting atop a nearby roof. Simply stand at the location in the above picture, jump forward, and press the crouch button when mid-air right above the object to slam down on it.

Follow Sam and Reach the Shrine

The next step is to follow him to a shrine so he can show the horizon to the Vault Hunter to prove that Kairos really is flat. The new objective marker will be updated on the map, so use ECHO-4 to find the trail leading up the cliff, with a couple of grapple points in between, and deal with Kratch spawns at the top.

Head up the cliffside to reach the shrine (Image via 2K)

With the Vault Hunter annoyed at this point, it is up to you to show him undeniable proof.

Reach the Wreck of the Big Carl

Head to the wreck for the next part of Flat Kairoser (Image via 2K)

Travel to the newly marked location on the map to reach the Wreck of the Big Carl, where several Rippers and Warhorn enemies await. Once they are dealt with, you must find three Surveyor Parts to progress.

Also Read: Borderlands 4 To The Limb It Redux walkthrough

Collect surveying equipment

The first one is located next to an outhouse:

First Surveyor piece location (Image via 2K)

The second is sitting atop a metal arch:

Second Surveyor piece location (Image via 2K)

The third is atop the wreck. It can be reached by grappling onto the roof of the wreck piece that the second Surveyor part is in (refer to the above picture), and it sits between two ammo chests:

Third Surveyor piece location (Image via 2K)

Once all have been obtained, it is time to find a place to set them up so they can survey the planet to capture its spherical shape to show to Skeptical Sam.

Read More: Borderlands 4: All Side Missions list

Find suitable launch site

Surveyor launch site map location (Image via 2K)

Head to the marked location on the map by following the objective marker. This will take the Vault Hunter to a faraway area that can only be reached by climbing up to a higher vantage point with the help of scalable walls and grapple points.

Follow the path up the cliff until this grapple and cross it (Image via 2K)

Reach the location shown in the above image and head past, while taking care of any enemy spawns like Creeps.

This will lead you to an open area with more enemies, where the objective trail goes up the wall. Scale it to get to the upper area.

Also Read: Borderlands 4 Waterfall Legendary grenade: Unique effect, stats, and how to get

Place atmospheric surveyors and activate them

Set down the collected surveyors here (Image via 2K)

Reach the final location with this large bone structure, eradicate all enemies around it, and then set the three surveyors down. Now interact with each one to have ECHO-4 launch them into the sky via a balloon mechanism.

Find the balloons

Now that the balloons have collected the data, it is up to you to track them down.

Find first balloon and get the balloon down

Tracking down the first balloon takes the Vault Hunter to the Shredded Summit. Since this is located far away, follow the map marker on the Digirunner. Reach the area, clear out the enemies, and shoot the balloon to have it plop down the surveyor machine to retrieve the photo.

Shoot at the balloon to be able to interact with the machine attached to it (Image via 2K)

Find next balloon and get the balloon down

The location of the second surveyor balloon (Image via 2K)

The second one is even further away. Once there, turn around to see the second balloon floating towards you, but it gets shot down. Thankfully, the third one is still intact and not far behind the second one that went down, headed towards a nearby shack (with a ladder). It gets snagged onto the antenna, so approach the shack and grapple the balloon when prompted to get it down, then interact with it.

Gett he third balloon down by grappling it (Image via 2K)

With all the photo surveyor data acquired, it is time to report back to Skeptical Sam.

Also Read: Borderlands 4: All Safehouses and datapad locations

Talk to Sam and upload Surveyor photos

Head to this location for the finale of Flat Kairoser in Borderlands 4 (Image via 2K)

The Vault Hunter must head to the Gilded Drop area to reach where Sam is. He is atop a tower, so approach it and grapple onto the ledge he is waiting on. After he is done talking, interact with the nearby terminal to upload photos:

The first photo shows nothing
Interact again to upload a photo taken from the third surveyor

This depicts Kairos' globe structure, but Sam remains skeptical even with proof shown to him. He wants to see the truth for himself, so he embarks on a journey to reach the Flat Kairos' edge by getting onto a hot-air balloon platform. Sadly, his contraption hits the nearby mountain, causing Sam to tumble out and fall to his death.

This wraps up the side mission Flat Kairoser in Borderlands 4, and you will be rewarded with cash, XP, a random weapon, plus the Flat as a Fritter cosmetic skin for both the Vault Hunter and ECHO-4.

Borderlands 4 is on PC, PS5, Xbox Series X|S, and Nintendo Switch 2.

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About the author

Siddharth is an esports and gaming writer at Sportkseeda. With nearly 10 years of experience in the industry, he also contributed to renowned publications like Gameffine (formerly IndianNoob), the British retro FPS magazine E1M1, and Gaming Purists, the latter being a passion project which he founded with friends.

Holding a Bachelor's degree in Computer Science, Siddharth's journalistic pursuits extend beyond reporting; he throws himself into the heart of gaming communities. His positive exploits in the industry have led him to interviewing Rohit Jain, a prominent Tekken 7 player from India.

Though he currently specializes in Nintendo, Overwatch 2, and RPG coverage, Siddharth's expertise spans a multitude of platforms and genres. He believes in doing extensive research across a mix of official, community-driven and diverse media sources for all of his article categories.

Siddharth has been an avid follower of Pewdiepie, which has also helped him expand his horizons to new gaming genres and titles. Beyond gaming, he indulges his love for literature with a particular fondness for horror and thriller novels. Moreover, Siddharth’s culinary enthusiasm for global cuisine enriches his palate.

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Edited by Siddharth Patil