Age of Calamity features several hidden playable characters beyond the main story cast. These characters are typically unlocked by completing specific challenges or requests that appear on the world map after certain story milestones. For example, the Great Fairies are unlocked by completing a series of challenges related to their fountains.
Keep an eye on new challenges and requests that appear, especially those with unique icons or descriptions. Some characters require you to complete a chain of missions. Unlocking these characters not only expands your roster but also provides new playstyles and strategic options for tackling difficult content. Consult a character unlock guide if you're struggling to find them all.