Nitro Powder

Powder packed with explosive power.
Found In Castle Cornelia
The dwarves need the Nitro Powder to blast open a channel to the outer seas, which allows you to continue your adventures. It can be found in Castle Cornelia's Treasure vaults, and is in fact the only Mystic Key-locked item required to advance the plot.
Compare Nitro Powder to other Key Items
Treasures: Containing Nitro Powder – 1 shown
Map
The specifics of where this treasure can be found
Notes
Castle Cornelia Found in a chest in the western treasure room
Bell Jolt Tonic

Related

TNT

Found In Castle Coneria
Nerrick the Dwarf needs the TNT to blast open a channel to the outer seas, which allows you to continue your adventures. It can be found in Castle Coneria's Treasure vaults, and is in fact the only mystic KEY-locked item required to advance the plot.