A Song of Water and Sand

Return to the castle entrance and find the room with the blood fountain.

Stand in the middle of the fountain and use the Blood Steal shard (a shard that allows you to absorb blood) to remove all the blood, revealing a secret passage downwards.

In the tall room, drop to the bottom and enter the doorway on the left to reach the Underground Waterway.

Proceed left down the hallway and defeat the first Axe Outsider enemy. Avoid its thrown axe, especially on its return trip as it can curve.

Defeat the bats that appear after the first Axe Outsider.

Defeat the second Axe Outsider.

Go through the doorway on the far left of the room into another tall room.

Note the Archdemon enemy. Hop across and go through the doorway immediately to your left.

Pass through this small room to enter the bottom of another tall room.

Climb this tall room and exit through the left door into a long room with water at the bottom. This room connects to the area under the drawbridge in front of the castle.

Go left and open the Blue Chest (#20) on the ledge above the water.

Return the way you came.

Ignore the door on the left and face the Archdemon. Be careful as its attacks are more aggressive than previous Demons.

Go down and through the next doorway on the left to find a Save Room (a room where you can save your progress). Watch out for the Poison Toad enemy.

After saving, go back into the previous room, check the Bookcase (#21), and drop down another level.

Go through the door on the left.

Drop down in this new tall room to face an Archdemon.

After defeating the Archdemon, drop down a level to face a Seeker enemy (an eyeball that moves fast and can turn you to stone).

Defeat the first Seeker.

Drop down a level to find another Seeker next to a doorway. Enter the doorway.

Equip boots and slide across the floor to deal with Poison Toads and Bats. A Seeker will also move along the ceiling.

Go to the left end of the room, loot the Blue Chest (#22), and return to the previous room.

Continue down through this room to reach the bottom level of the tall room.

Watch out for a Poison Toad at the bottom and any that may follow.

Destroy the leftmost wall to find an MP Max Up (#23).

Go through the door on the right into a long hallway.

Immediately face a Seeker and an Archdemon. Use Cerulean Splash (a water-based attack) if possible to hit both.

Hop over the Seeker when it approaches and attack the Archdemon.

To the right of them, you will find an Axe Outsider and an exit. Kill the Axe Outsider quickly, dodge its axe, and go through the exit.

Enter a tall room with a door on the opposite side.

Go through the door on the right, kill the Seeker, and open the Blue Chest (#24).

Return to the previous tall room.

Drop down a level, watching for Bats.

Continue down to the water at the bottom and go through the doorway on the right.

In the next water-filled room, kill the Deeseama enemy (a sturdier water enemy that shoots like a rocket).

If you do not get the Aqua Stream shard (a shard that allows water-based attacks) from defeating the Deeseama, go through the doorway on the right and return to this room to fight it again. The Aqua Stream shard has a 12.5% drop rate. You need to kill eight Deeseama enemies to progress.