This is an extremely short puzzle on how to open a locked gate for a shipwreck in Erinnyes Forest by finding 3 keys. Inside the shipwreck is a Precious Chest and a Hydroculus. But I made a separate post instead of combining all of them in my Hydroculus guide.
Teleport to Lumidouce Harbor north waypoint and look to your west for a shipwreck with a locked gate. If you interact with it, the game wants you to offer 3 keys to unlock the gate.
The first key can be obtained by defeating the Treasure Hoarder enemies on top of the ship and unlocking the treasure chest. The first key is inside that chest.
The second key is inside a bird nest on top of the shipwreck. Just climb the ship to the pointy top and you will see a bird nest.
The third key is on the other half of the shipwreck, you will see a small bag near stones. Tap on the Dig option and you will get the last key.
Use all 3 keys to unlock the gate and you can get the Hydroculus and a Precious Chest.