Who's-Who,[9] also known as Who of the Droplets,[3] is a pirate who acted as one of the Tobiroppo, the strongest six Shinuchi of the Beasts Pirates, prior to Kaidou's fall from power after the Raid on Onigashima.[10]

Over a decade ago, he served as an agent of CP9 before his failure to guard the Gomu Gomu no Mi led to his dismissal from service and imprisonment.[4] Upon escaping, Who's-Who turned to piracy, becoming captain of the Who's-Who Pirates before eventually joining the Beasts Pirates.[5][3]

Due to his actions and role, Who's-Who is a supporting antagonist in the Wano Country Arc and the Oni Child Yamato's Golden Harvest Surrogate Pilgrimage cover story.