Hello Travelers! Today I’m bringing you the guide to the solving the “Great Amakumo Peak” underwater puzzles on Seirai Island. Hope it helps!
Puzzle Rewards:
Luxurious Chest*2, Precious Chest*1, Achievement “Great Amakumo Peak”
Steps:
I. Stone Tile Puzzle
There is a maze inside the lake that surrounds Amakumo Peak. Solve this puzzle and you can get underground. The location of the first stone tile puzzle is shown below:
Go to Amakumo Peak and find this tile puzzle. There are many monsters around so be ware of them.
Solution: Light up the tiles marked in the picture, and start the mechanism on the right.
The water drains when you light up the tiles.
From there, go through the Phase Gate near the tiles and you can get an Oculus in the air.
II. Underground Puzzles
You can get underground after solving the tile puzzle. Gilde down from the entrance on the ground and you will see a locked mechanism on the left. Defeat the two monsters nearby to unlock the mechanism. Activate it to drain the water again.
III. Red and Yellow Gate Puzzle
You will see a red gate at the bottom of the cave after draining the water for the second time. Fly towards the gate.
The gates in the underwater maze has three colors: red, yellow and blue. The mechanisms of each color control all the gates of the corresponding color. The mechanism shows only two patterns: a horizontal one and a vertical one.
Solution: The gates open when you start a gonmechanism. But a single mechanism controls multiple gates, so if you open the first gate to find the second gate is still closed, you will have to go back to the first gate and adjust the mechanism.
Start the red switch first, follow the Seelie and get inside:
Then start the yellow mechanism, get through the gate and start the red mechanism. After that, go back and turn off the yellow mechanism you just turned on.
And then follow the Seelie upstairs, you will find the two gates there are opened already. Just go through them.
Continue to guide the Seelie until the end of the path, and then follow the next Seelie ahead to the next gate. You will see:
Don’t start the mechanism when you reach there! Go up the stairs on the right and go through two gates in red and yellow respectively (already opened), you will see:
Make the pattern on this mechanism vertical, go back to the Seelie, and switch the pattern on the yellow mechanism to a vertical one as well, which opens the gate in front of the Seelie. Follow it through.
The Seelie will then fly up. You can climb up where it is. Guide the second Seelie until the end of the path, and then follow the third Seelie along the way until you get here:
Go find the mechanism of the gate on the left first. Go staight ahead and you will see a red gate. Go along the path on its left side.
Follow the path till its end and you will see the mechanism for the red gate there. Make its pattern vertical.
Go back to where the red gate is, you will find that the gate has opened, get in and switch the blue mechanism to vertical form, which controls the second blue gate. Go back to the second blue gate and switch the yellow mechanism to vertical as well. Go back to the first blue mechanism and pass through the yellow gate. You will also find that the first blue gate was opened, as shown in the screenshot below:
You will find Electroculus*1, Luxurious Chest*1 inside. You will get the achievement “Great Amakumo Peak” after opening the Luxurious Chest.
Activate the last mechanism in the secret room to lower down the water level again.
There are three chests at the bottom of the cave. Don’t forget to loot them. That’s it! Puzzles solved!
Summary:
This quest takes about 20 minutes to complete. The puzzles are not very complicated but the routes are, so I’d recommend you to follow this guide throughout. 
