One Piece: Grand Battle - Hidden Characters

Smoker:
Win the game with Roronoa Zoro Hard mode suggested. Can be unlocked on any difficulty setting.

Wiper:
Win the game with Monkey.D.Luffy Hard mode suggested. Can be unlocked on any difficulty setting.

Omu:
Win the game with Tony Tony Chopper Hard mode suggested. Can be unlocked on any difficulty setting.

Mr Crocodile:
Win the game with Nico. Robin Hard mode suggested. Can be unlock on any difficulty setting.

Enel:
After unlocking all the other characters above win the game with Wiper and Monkey.D.Luffy on Hard difficulty setting. Refer to unlocking Wiper.

Hina:
Once you've gained Enel, win the game with Usopp on Hard difficulty setting.

Bon Clay:
After gaining Hina, win the game with Sanji on Hard difficulty setting.

Portgas.D.Ace:
After unlocking all characters above, beat Training mode with all of Luffy's crew and then win the game with Smoker on Hard difficulty setting.

Red Hair Shanks:
Once you've gained every other character, win the game on Hard mode using all of Luffy's crew then win the game once more with Luffy on Hard mode.

Luffy's Crew:
Luffy's crew consists of Monkey.D.Luffy, Roronoa Zoro, Nami, Tony Tony Chopper, Usopp, Sanji, Nico and Robin.

Unlock The Marine HQ:
Play the BOMB x51 catching game in Training mode.

Unlock The Windmill Village:
You can unlock this stage by collecting all the cards. This stage can only be made available after you unlocked Enel.

Alternate Costumes:
Several Characters mostly Luffy's crew; wich consist of Luffy, Zorro, Sanji, Ussop, Chopper, Nami and Nico Robin have 3rd and 4th Alternate costumes which are unlocked by doing several tasks.

Luffy's Crew 3rd alternate costume:
In training mode, complete the training list with Luffy , Zorro, Sanji, Ussop, Chopper, Nami and Nico Robin.

Luffy's Crew 4th alternate costume:
To do this, you must choose the VS option, go against computer in Hard with 3 rounds and try to finish all the rounds with the super level 2 special.

Wiper's 3rd Costume:
After getting all the costume, complete Training mode with Wiper again.

Shanks 3rd and 4th Costume:
After getting Luffy's pirate 3rd & 4th costume, complete Training mode with Shanks.