Fiore is the team's main offensive spellcaster with a good variety of wind and darkness-based attacks designed to pummel groups of enemies. She also has basic healing, recovery, and revival spells that helps a lot in case of emergencies when Miki is silenced or knocked out. She also has access to two of the most useful skills in the game against bosses or tough enemies: Void (removes all buffs on the target) and Sacred Pain (lowers target's elemental resistances). These skills prevent enemies from having buff and resistance advantages.
For the spreadsheet Skill List, follow this link.