Another way to get Nico Robin (Mrs. Sunday): In 'Crocodile Adventure Mode', Nico Robin is the first ally you get. Get her, then win a battle with her.
Buggy: To unlock Buggy as a Captain in Adventure Mode, in Luffy's Adventure Mode, defeat Crocodile in Alubarna on the Alabasta Kingdom Sea Area, and recieve the rank "Top Pirate in Town", and before or after the credits, you will recieve Buggy as a Playable Captain in Adventure Mode.
Crocodile: To unlock Crocodile as a playable captain in Adventure Mode, in Luffy's Adventure Mode, defeat Crocodile in Alubarna on the Alabasta Kingdom Sea Area Map, and after you defeat him, get the rank "Top Pirate on the Island". Before or after the credits, you will recieve Crocodile as a Playable Captain in Adventure Mode.
Eneru: In Crocodile's adventure mode, get Eneru as your ally in the Jaya area, and win a battle using him.
Luffy's Crew: In 'Luffy's Adventure mode', your crew will be...
Mihawk: In Chaser's (Smoker) adventure mode, after recruiting Mihawk, win a battle using him.
Mr. 2 Bon Clay: In Crocodile's adventure mode, get Mr. 2 as your ally, and win a battle using him.
Nico Robin: In Luffy's adventure mode, get her as your ally at the end, and win a battle using her.
Ohm: In Crocodile's adventure mode, get Ohm as your ally in the Jaya area, and win a battle using him.
Shanks: In Buggy's adventure mode, recruit Shanks and then win a battle using him.
Trace (Ace): In Buggy's adventure mode, recruit him in Drum Island, then win a battle using him.
Ussop: To unlock Ussop as a Playable Captain in adventure Mode, defeat the final boss in Luffy's, Buggy's, Crocodile's, AND Chaser's Adventure Modes. After the credits of the last Adventure Mode(No order is required), you will unlock Ussop as a Playable Captain. In Ussop's Adenture Mode, you can use make a team of ANY Pirates you have unlocked!
Zolo: Auto Attack Power-up As Zolo, press A then X. Zolo's fist will be blue or have blue flames around it. You'll lose the blue fist when you get hit.
