Your base of operations, the 'Treasure Vault', is more than just a place to store your loot. It's a hub that can be upgraded to provide various benefits. By completing certain side quests and investing gold, you can unlock new facilities and improve existing ones. Key upgrades include:
- Monster Barracks: Increases the number of monsters you can recruit and store.
- Item Shop: Offers a wider selection of healing items, slingshot ammo, and crafting materials.
- Cafeteria: Provides stat-boosting meals for your party before expeditions.
- Training Grounds: Allows you to passively level up monsters not in your active party.
- Treasure Appraisal Room: Speeds up the appraisal process and increases the value of appraised treasures.
Prioritize upgrading the Monster Barracks early to expand your recruitment options. The Item Shop and Cafeteria are also crucial for maintaining your party's strength during longer expeditions. Regularly check with the NPCs at your base for available upgrade options.