As you venture through the vast biomes that extend from the Core in Core Keeper, you’ll stumble upon various ancient ruins, some exposed due to looting or the passage of time, while others remain securely sealed. While many of these ruins hold outdated technology or minor treasures, some are much more significant.
Among them, one ruin floats on a solitary island in the Sunken Sea. If you pass by, you’ll notice a chest concealed behind an unusual locked door. Digging won’t get you through, so to access the treasure inside, you’ll need to harness ancient technology to craft the Admin Key.
How to Prepare and Locate a Forlorn Metropolis
The Admin Key is a special item used to unlock the Sunken Shrine in the Sunken Sea. To create it, you’ll need three unique crafting materials along with the purchasable Empty Crystal recipe:
- Shutdown Protocol
- Anomaly Report
- Overwrite Transport
To reach the Sunken Sea, you must defeat the first three bosses – Glurch, Ghorm, and Malugaz. Place their dropped trophies in their respective totems at the Core to remove the Great Wall, and locate the biome beyond its border.
These three materials can only be found in exclusive areas of the Forlorn Metropolis sub-biomes, situated in the Sunken Sea and often appearing amidst the open water, unless they intersect with land or other mid-game biomes.
Before you set out, ensure you have at least reinforced Octarine Armor, some powerful weapons, bridges, and enough food and potions. The sub-biome is extensive, and you’ll encounter multiple enemies in a single room who can hit hard with long-range magical attacks, even if you’re prepared.
Having a Boat is essential for traversing the waters easily without the hassle of building numerous bridges. You can craft the basic model at a Boat Workbench using 80 Planks, 50 Scarlet Bars, and 20 Mechanical Gears.
If you’ve already explored the Desert of Beginnings and started creating Galaxite Bars, the Galaxite Chakram is an excellent weapon for the Forlorn Metropolis because it frequently bounces off room walls.

Once prepared, begin boating across the expanse of the Sunken Sea, concentrating on the widest water areas and searching for large structures in the water.
Forlorn Metropolis sub-biomes will appear as square-shaped connections of rooms and hallways, unlike the land formations, with their building blocks displayed in light and dark blue-green colors on your map.
A helpful strategy to locate a Forlorn Metropolis is to first boat around and identify at least one edge of the Sunken Sea. This will help you establish some boundaries, increasing your chances of discovering one.
Each Forlorn Metropolis will always feature two to four open entrances for docking, which may occasionally harbor enemies and items like the Vending Machine that sells various food dishes.
Inside, you will face Caveling Scholars and Core Sentries, both capable of launching magic attacks and the sentries utilizing an area-of-effect stomp.
How to Locate the Broken Cores
Within these areas, you can find various unique items, such as Crystal Lamps and Ancient Chests containing Sunken Sea loot like Octarine Ore. However, the main goal is to discover the special Broken Core Room scenes.
The Shutdown Protocol, Anomaly Report, and Overwrite Transport can only be obtained by interacting with the Broken Cores found in these specific Forlorn Metropolis sub-biomes that are typically larger than usual.
- Shutdown Protocol: Approximately 550 tiles from the Core.
- Anomaly Report: Approximately 650 tiles from the Core.
- Overwrite Transport: Approximately 750 tiles from the Core.
Finding at least one of the sub-biomes containing a part of the Admin Key will assist in determining the locations of the other two, as they are usually in proximity to each other.
These rooms are among the largest within the sub-biome and are generally situated in the center, displaying a unique appearance on the map.

They will always feature two to three lines intersecting with a gray square, which represents the Broken Core, but will lack the blue or green centers that mark the City Park and City Plaza scenes.
Upon discovering the Broken Core Rooms, approach the Broken Core and interact with it. A mini-inventory will appear, revealing one of the three crafting materials.
Be sure to inspect the Ancient Chest found in each of the three Broken Core Rooms, as they contain unique crafting materials necessary for making the Phantom Spark bow.
How to Craft the Admin Key

After collecting the three essential items from the Forgotten Metropolises, the final component you’ll need is the Empty Crystal.
This recipe can be purchased from the Cloaked Merchant for 3,000 Ancient Coins after you’ve activated the Core by placing all three trophies from the early-game bosses into their corresponding statues.
After defeating Ghorm the Devourer, the Cloaked Merchant and their furniture item will become available. As with other NPCs, you can house them in your base by placing their Mysterious Idol in an appropriate room.
Next, add the Empty Crystal to your hot bar and ensure you have the Shutdown Protocol, Anomaly Report, and Overwrite Transport in your inventory simultaneously, as it won’t work otherwise.
Activate the Empty Crystal to trigger a progress bar on your screen. Once filled, the three items will merge with the Empty Crystal to create the Admin Key, allowing you to unlock the Sunken Shrine.
How to Find and Open the Glyph Parchment Shrine

The Glyph Parchment Shrine can be found in the open waters of the Sunken Sea, located 500 tiles from the Core.
It appears as a small, lightbulb-shaped island featuring a ruins room similar to the Musical Note Rooms but with a visible Titan Chest inside and a large, ornate door that has a diamond-shaped hole.
If you’ve discovered the Forlorn Metropolis containing the Shutdown Protocol, there’s a good chance the Sunken Shrine is nearby, so you can easily boat there from the Forlorn Metropolis.
Once you find the shrine, approach the door and interact with it. This will open a mini-inventory where you can place the Admin Key, unlocking the door.
Inside, you’ll find several breakable items from the Forlorn Metropolis, unique furniture, and a Titan Chest hidden behind a Throne, which contains valuable loot: 25 Gold Bars, 15 Ancient Gemstones, and the unique Glyph Parchment recipe needed to craft the Phantom Spark bow.