During the Reverse Mountain Arc — which is most likely to happen at the end of Episode 1 or in Episode 2 of "One Piece" Season 2 — Luffy and his crew meet a mercenary named Miss Wednesday. While she's initially their adversary, the Straw Hat Pirates learn that she's not actually subservient to the criminal Baroque Works organization like she claims, but attempting to infiltrate it for the sake of the Kingdom of Alabasta. Her true name, it turns out, is Nefertari Vivi and she's Alabasta's princess.
From that point on, Vivi joins the Straw Hat Crew — some might argue unofficially, whereas others consider her as valid a member as can be. Full member or not, Vivi accompanies the Straw Hats on a number of adventures across multiple islands on their way to Alabasta. Since Season 2 is most likely to conclude at some point during or at the end of the Alabasta Arc, Vivi may well be a Straw Hat Pirate for the majority of the upcoming season.
Vivi's closest companion, meanwhile, is a large, rideable duck named Karoo, whose realization in live-action will present a similar challenge to Chopper's. Karoo is arguably the best comic relief character in the Alabasta Saga, so his introduction is one further reason to anticipate Vivi's first appearance in live-action.
