Key items are essential for progression, unlocking new areas, or revealing secrets. Consumables are your lifeline in dungeons and tough battles. Always keep a healthy stock of the latter. Key items include:

- Moonbrooke Staff: Transforms the Princess.
- Eye of Rubiss: Reveals hidden paths.
- Silver Key: Unlocks silver doors.
- Gold Key: Unlocks gold doors (found later).
- Watergate Key: Opens specific water gates.
- Five Sigils: Required to open the path to Hargon's Castle.
- Boat: Allows sea travel.
Essential consumables:
- Herb: Restores a small amount of HP.
- Antidote: Cures Poison.
- Wake-Up Powder: Cures Sleep.
- Medical Herb: Cures Paralysis.
- Warp Wing: Returns you to the last town visited.
- Magic Water: Restores MP (rare and valuable).
- Leaf of the World Tree: Revives a fallen ally (very rare).
Stock up on Herbs and Antidotes regularly. Magic Water and Leaves of the World Tree should be saved for critical moments.