As you explore the expansive biomes that branch out from the Core inCore Keeper, you’ll come across all sorts of ancient ruins, both open due to looting or time passing or still locked up tight. Most of them just have some old technology to sell or a few useful treasures, but certain ones contain far more.

Floating on a lone island in the waters of the Sunken Sea sits one of those ruins, and passing by it will show you a chest hiding inside behind a strange locked door. There’s no digging through, so if you want the treasure inside, you’ll need to utilize old tech and make the Admin Key.

Player character about to craft an Octarine Breastplate and showing the stats of it in Core Keeper.

How To Prepare And Find A Forlorn Metropolis

The Admin Key is a unique item used toopen up the Sunken Shrine in the Sunken Sea, and it’s made up ofthree other unique crafting materialsand the special,purchasable Empty Crystal recipe:

You can reach the Sunken Sea by defeating the first three bosses –Glurch,Ghorm, andMalugaz–putting their dropped trophies into their respective totems at the Core, removing the Great Wall, and finding the biomepast its border.

Player character wearing Galaxite Armor using a boat to cross the Sunken Sea in Core Keeper.

These three materials can only be found inspecial scenes in Forlorn Metropolis sub-biomes, which arelocated in the Sunken Seaand generallyfound within the open waterunless one happens to intersect with land or another mid-game biome.

You’llwant at least Octarine Armor that’s been reinforced, a few good weapons, bridges of some kind, andplenty of food and potions, as the sub-biome is massive, and you’ll bedealing with multiple enemies in a roomthat can pack a punch withlong-range magicif you’re unprepared, andwear down your armor’s durabilityeven if you are.

Closer view of a large size Forlorn Metropolis in the Sunken Sea with land masses and water around it in Core Keeper.

Anotherkey itemfor finding them is aBoat, which allows you tocross the waters quicklyand without wasting tons of bridges, and thebase typecan becrafted at a Boat Workbenchwith80 Planks, 50 Scarlet Bars, and 20 Mechanical Gears.

If you’ve already been to the Desert of Beginnings and started making Galaxite Bars, theGalaxite Chakram is a fantastic weapon for the Forlorn Metropolis due to how often it bounces off the wallsof the rooms.

Player character crafting an Admin Key in their base which shows a progress bar and blue light around them in Core Keeper.

When you’ve got everything, startboating across the open watersin the Sunken Sea, focusing on thewidest areas of water in the middleof the region, and looking formassive structuresin the middle of the water.

Forlorn Metropolis sub-biomes always show up as asquare,connected sections of rooms and hallways, different from the land generation, and their building blocks show up aslight and dark blue-green colors on the map.

Close up view of the Sunken Sea on the map with the player next to a lightbulb-shaped island in Core Keeper.

Agood method for locating a Forlorn Metropolis is to boat around and find at least one border of the Sunken Sea first. You’ll mark out some limits and a range, and you’re likely to find at least one while you’re doing this.

Each one will always haveat least two to four open entrancesyou can dock at, whichsometimes have enemies and furniture pieceslike the Vending Machine, which sells a handful of food dishes.

Inside the Forlorn Metropolises, you’ll befighting Caveling Scholars and Core Sentries, both of whichuse magic attacksand anAOE stomp for the sentries.

How To Find The Broken Cores

You canfind various unique furniture items, like Crystal Lamps, andAncient Chests containing Sunken Sea-related lootlike Octarine Ore inside, but themain thingyou’ll need to find is the specialBroken Core Room scenes.

The Shutdown Protocol, Anomaly Report, and Overwrite Transport canonly be found when interacting with the Broken Coresfound in these scenes, and these arefound in specific Forlorn Metropolissub-biomes which arelarger than usual.

If youfind at least one of the sub-biomes containing an Admin Key part, you’re able to use it to help triangulate the locations of the other two, as it’ll be near them both.

These rooms areone of the largest of all sceneswithin the sub-biome,generally in the center, and have aslightly different visual appearance on the map.

They always havetwo to three lines intersecting with a gray square, which is the Broken Core, but they willlack the blue or green centersthat theCity Park and City Plaza scenes have.

When you find the Broken Core Rooms,approach the Broken Core and Interact with itto bring up amini-inventorythat containsone of the three crafting materials inside.

Make sure tocheck the Ancient Chest that’s always in each of the three Broken Core Rooms, as they each contain a unique crafting materialneeded to make the Phantom Spark bow.

How To Craft The Admin Key

When you’vegot the three piecesfrom the Forgotten Metropolises, the last thing you’llneed is the Empty Crystal.

This recipe can only bepurchased from the Cloaked Merchant for 3,000 Ancient Coinsafter theCore has been activatedby putting all threeearly-game bosses' trophiesinto theirrespective statues​​​​​​at the Core.

TheCloaked Merchant and their furniture item are unlocked after you beat Ghorm the Devourer, and like other NPCs, they can be housed in your home by placing their Mysterious Idol in a suitable room.

Next, put theEmpty Crystal into your hot bar, and make sure you have theShutdown Protocol, Anomaly Report, and the Overwrite Transport in your inventoryat the same time, as it won’t work otherwise.

Use the Empty Crystal, and you’llget a progress baron your screen. When it fills up, thethree pieces will combine with the Empty Crystalto become the Admin Key, and now you may open the Sunken Shrine.

How To Find And Open The Glyph Parchment Shrine

The Glyph Parchment Shrine is in theopen waters of the Sunken Sea, and it’salways located 500 Tiles from The Core.

It appears as asmall light-bulb-shaped island with a ruins roomthat resembles the Musical Note Rooms found randomly but with avisible Titan Chestinside and a large,decorated door with a diamond-shaped hole.

If you’vefound the Forlorn Metropolis with the Shutdown Protocol inside it, the Sunken Shrine has a good chance of being very closeto it, and you can boat from it to the shrine’s island.

When you find the shrine,approach the door and Interactwith it. You’ll get amini-inventoryyou canslot the Admin Keyin​​​, and doing so will open the doors.

Inside, you’ll find several pieces of Forlorn Metropolis breakables and unique furniture, and aTitan Chest behind a Thronethat contains some valuables:25 Gold Bars,15 Ancient Gemstones, and theunique Glyph Parchment recipe, which is required tocraft the Phantom Spark bow.