Yusidra Caves

 is a dungeon in Ragnarok DS. It's a low-level area full of Porings and Masterings. An item known as a Clean Stone drops from the monsters here.

Story
A Detale that drops an Emperium resides in the deepest parts of the caves. One group of adventurers' attempt to fight the dragon ended in tragedy and resulted in that part of the Yusidra Caves to be sealed off and hidden from other adventurers.