Core Keeper: Sunken Sea Biome Phantom Spark Guide (How to Find)

After you have explored for a bit, it’s somewhat easy to find the large fortress containing the broken core idol holding a admin key material.

Once you find a fortress check the bottom to see if it has 4 statues or a shipwreck, that guarantees an admin key part. Once you find one, circle it to check the size of the big fortress, then look on your map for areas that could potentially have a fortress of that size.

There are only 3 big fortress’ and each have a broken core idol with a admin key part inside of them, along with a chest next to it containing one of the materials needed to make the bow after the glyph parchment is obtained (Glyph is found on the treasury of admin keys island).

Side chest materials for phantom spark include:
Channeling Gemstone
Fractured Limbs
Energy String

(If you are not aware, once you get the shutdown protocol, anomaly report, and overwrite transcript from the fortress’ broken core idols, you can craft the admin key from an empty crystal purchased from a caveling merchant).

As for the mythical treasury of admin keys, it’s all luck. I circled many islands until I found it by itself (it can be connected to a main island, so best to check all islands edges). You will need to use the admin key to open the island door, and inside the chest will have the Glyph Parchment. You can then activate the glyph, like you would the rune parchment, and with all the required items in your inventory, it will create the Phantom Spark.

I’ve heard different rumors on block radius formations of the fortress’ based on the titans location, however I could not find anything consistent, but it looks like some sort of pattern on my map. I have seen other maps where it’s a complete different spawn formation with no clear pattern.

Bonus: You can use the phantom spark to spawn phantom cavelings to attack enemies.