Brigitta Lycaon, Grand Trad’s igniter merchant, speaks to you as soon as you reach the capital. Her bond gives you access to the Merchant, one of the most unique Archetypes in Metaphor ReFantazio. Getting the right answers with her already nets you some magla to spend researching this lineage.
You need Wisdom rank two to get Brigitta to open up. She then gives you the A Bullish Embargo quest to take down a monster in Belega Corridor, which isn’t too difficult. Wrap up the quest to unlock Brigitta’s bond (Or Social Link, if you’re used to Persona terms) and unlock the Merchant Archetype.
