This requires Imagination Rank 3 ... The Thief is a rather unique Archetype in Metaphor: ReFantazio, unlike a lot of the early-game Archetypes. To unlock it, you will need to befriend Heismay ...
The campaign of Metaphor ReFantazio takes players across the vast map of the United Kingdom of Euchronia, and within the story are present a whole host of side quests to undertake.