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One Piece: Grand Adventure Cheats, Codes, Hints, Tips
Unlockable: Hawk-Eyes Mihawk
Go into Chaser's adventure mode, use him once in battle after he joins the crew.
Unlockable: Eneru
During Mr. 0 Crocodile's adventure mode, you must use him once in battle when he joins the crew.
Unlockable: Chaser
You must access Chaser's adventure mode. First, level him up, then use his Secret Attack.