Key Items are unique, story-related items that often unlock new areas, progress the plot, or provide permanent buffs. These are typically acquired automatically through story progression or by completing specific Cie'th Stone Missions. Examples include the various 'Glyphs' found on Gran Pulse that unlock access to Taejin's Tower. Collectibles, on the other hand, are often optional and include things like hidden treasure spheres, data logs, and fragments. Data logs provide additional lore and backstory, enriching the game's narrative. While not strictly necessary for completing the game, collecting all key items and exploring for hidden treasures can provide significant advantages and a deeper understanding of the world of Final Fantasy XIII. Always check your inventory for new key items after major story events.
