Waterfall Cave - Liquid Metal Sword Quest Walkthrough
This side quest will reward you with the Liquid Metal Sword, one of the more powerful weapons in the game and also a weapon great for hunting metal slimes. If you're unfamiliar with the Dragon Quest series, metal slimes give the most EXP of all enemies you can fight but they run quickly from battle and are difficult to kill.
To get started on this side quest you'll want to head to the town of Dunplundrin which is in the western part of the world, just south of Zamoksva, the area where Alena begins the game. There isn't much to do in this town except pick up the Karstaway Stone which is found on the beach.
At night time you can see this stones location but the tide is too high to grab it (screen shot on the left). During the day the tide is rescended a bit (screen shot on the right) which allows you to grab the stone. To pick up the stone you'll need to open up the options window and select the 'Examine' option while standing in the right location. Use my pictures below for guidance locating the stone.
Once you've got the stone in hand our next stop is going to be Waterfall Cave, it's actually just east of Femiscyra but mountains block the way. I'd recommend Zooming to the Minikin's Dominion then sailing a bit south and docking on land to get here. Alternatively if you haven't been to the Minikin's Dominion, Zoom to Mintos, that's close enough.
Inside the waterfall cave you'll want to go into your inventory and use the Karstaway Stone when standing near the stairs leading down into the water. This will clear the water away for you can give you access to the area beneath where you'll find the Sands of Time.
To proceed any further through the dungeon you will need the Ultimate Key, which if you've been following my walkthrough up until now you should have. If not, you get it in Femiscyra I would guess about half way through the game. This key will let you open the large metal door on the other side of the Treasure Chest which had Sands of Time in it.
The rest of the dungeon is a bit more like a dungeon and not just a room with a chest. Aside from the Liquid Metal Sword there are three items you can find throughout the dungeon in chests, a list of those items is below.
Items to Find:
Death Mask (Cursed)
Liquid Metal Sword
Once you've found everything Evac out of the dungeon and return to wherever you were previous in the story.