This dungeon is actually a bit easier than the last one.
When you get to the boss, keep everyone's health high and watch out for his "Rampage" move as it does about 500 damage to all.
When you're done here, go in to the cave entrance. Here you'll meet Mimi, who says you need to go to the Village of Water People.
Exit the cave to the east, go to the Village of Water People, and watch the scene there. (Note: there are two treasures in the village; an Iron-tight Defense bit northeast of the Item shop, and a Full Hit bit across the bridge in the southwest.)
Now go to Devilmeet Cave.
- Brutal Viper (Weak to Knuckle, Rod)
- Prismic Maris (Weak to Gun)
- Rock Golem (Weak to Ball)
- Disinfecting Herb - Cure poison
- Magical Element - Heal 75 MP
- Evolutionary magic stone - Upgrade bits
- Total healing medicine - Heal all HP
- Fastest Action (Bit) - Always go first
- Increasing Compatibility of weapons (bit) - Allows all bits to be used regardless of the weapon type