Luffy - Captain, Wants to be Pirate King

Zoro - Swordsman, Wants to be world's greatest swordsman

Sanji - Cook, Wants to find All Blue

Nami - Navigator, Wants to make a map of the world

Usopp - Sniper/Technician, Wants to be a brave sailor of the seas was it? forgot

Chopper - Doctor, Wants to be best doctor

Nico Robin - ???

Whats Nico Robins purpose? I liker her and she's a great character but whats her ambition and job?