Cave of Mysidia (FF2DoS)

[Erdrick Holmes]

I already used both masks so far (one on the statue in the city and one to make the doppleganger go away) and I searched from top to bottom of that dungeon in the Cave. What exactly am I looking for? The walkthroughs at game FAQs are NOT helping. Can somebody maybe show me some maps of that dungeon or provide some info?

[theundeadhero]

At the bottom of that cave their should be a crystal staff you need to acquire. Sorry I can't provide a map.

[Erdrick Holmes]

I noticed four tresture chests next to eachother but I have no clue how to get to them.