Curran serves as the party's "Vanguard"—basically their frontline tank. She wields a greatsword and locks down enemies in melee combat, holding the line while others deal damage from safer positions.
What makes her stand out is that she's the only non-human party member, a "Dragon Person" (half-dragon, half-human hybrid) with a suite of racial abilities that come with the territory. Fans often note that her heritage gives her some serious advantages in a fight.
She didn't start with this group, though. Her previous party treated her poorly, using her as a glorified meat shield—just someone to soak damage and keep enemies busy while they did the actual work. After that experience, she joined up with her current party, presumably hoping for better treatment. It's a common arc for tank characters, but it hits different when it's actually happened to someone.
Content compiled by AnimeList.moe from publicly available sources.