Located underneath the Crystal Lake in Rosalia, the caves are home to one of the legendary Fatestones, the Aquamarine. While on the boat floating on the Crystal Lake you can choose to dive underwater. If you choose to dive where you see ripples on the water's surface then you will enter one of the 4 Aquamarine Caves.
Caves A, B & C are dead ends, but contain treasure and monsters to fight. Aquamarine Cave D (and then Cave E) holds the Fatestone.
Pass through Cave D and into Cave E. Avoid the first set of spewing statues; getting hit will instantly kill you and result in a game over. Take the right fork towards another set of statues. When you are in the middle of them, take the hidden path left to the narrowing end. Touch the strange glowing crystal orb, which will warp you back to Cave D, but the way will now be open to the Aquamarine.
Follow the tunnel and approach the Aquamarine room to face the Guardian, Ghost Ship.
Defeating the Ghost Ship will allow you access to the much sought after Fatestone, which you may, or may not, choose to give to Prince Neidhart.
- Find the Aquamarine
- Find Chests
- Disarm Traps
- Find Ore
- If you do not obtain the Fatestone before ER 15, even if you have triggered the quest, then someone else will beat you to it and you will never be able to obtain it in that playthrough.