Wiki
Wiki is a Golden helicopter monkey that can turn into a Bell and is Zack's best friend. In the Japanese version of Zack & Wiki:Quest for Barbaros' Treasure, he is known as Charlie Bell. Wiki was once Barbaros' right hand man but when Barbaros sought world domination Wiki itemized him by distracting him with a steak. Wiki has a high pitched voice which makes many people think he's a girl. Wiki usually refers to Zack as "boss or "big guy".
Wiki is thought to have been sucked into the black hole along with Barbaros but he somehow survived but lost all his memory. Wiki's favourite food is pistachios but he has never shown it.
It is unknown if there are more helicopter monkeys like him.
Relationships
Zack
Zack is Wiki's best friend and the two treat each other like brothers. Wiki is always looking to help Zack, though will run away if Zack is in mortal peril, bragging that he can just fly away. Wiki is always encouraging Zack or pointing out potential hazards on their journey. When Wiki apparently sacrifices himself during the final battle, he makes Zack promise that whatever happens, he doesn't want any tears. Days later, it is revealed that upon hearing the news of Wiki's death, the Sea Rabbits went into a state of depression. Zack, taking it worst of them all, became despondent and isolated himself from the group. When the Sea Rabbits hear the sound of Wiki's bell, Zack is the first, and possibly the only one, to notice, and rushes outside, along with his friends, to find a treasure chest washed up on shore, carrying Wiki, who is still alive after all.
Johnny Style
Wiki is good friends with Johnny, despite his cowardly actions. When Johnny abandons Zack and Wiki in the beginning of the game, Wiki, apparently frustrated, remarks that at least Johnny got away. Regardless, Wiki likes Johnny and treats him as any friend would.
Captain Rose
Not much is known here. Rose apparently thinks that Wiki is adorable but it is unclear Wiki's thoughts on this, though it is highly possible that it annoys him, as he likes to be taken seriously, most of the time.