Pete
A follower of Maleficent and former captain of a steamboat, Pete has become a commander of Maleficent's Heartless army. Pete used to live in Disney Castle, but was cast into another dimension by King Mickey for causing mischief. His original name was Bootleg Pete, and he holds the distinction of being the oldest continuous Disney character, appearing as early as Walt Disney's Alice Comedies. In Kingdom Hearts II, he is voiced by Jim Cummings.
Although he plays an antagonist role in Kingdom Hearts, he mostly just a comic-relief character and doesn't pose much of a threat (mostly because he's a complete idiot).
History
Many, many years before Kingdom Hearts II, Pete worked as the captain of a steamboat. His deck hand was none other than the future king of Disney Castle, Mickey Mouse. This past association causes Pete to refer to Mickey as "the Boat-Boy King."
At some undetermined point, "a long time ago," Pete turned to evil, and King Mickey banished him to another dimension. He found aid in the form of Maleficent, who helped him escape his exile. In return, Pete became a commander in her Heartless army, and traveled around many worlds building up more and more legions of Heartless to help her plot of world-domination.
Kingdom Hearts II
Pete is first encountered outside Yen Sid's Tower, having sent in a squad of Heartless to turn the powerful sorcerer Yen Sid into a Heartless to act as Pete's bodyguard. But Sora, Donald and Goofy showed up, informing him of Maleficent's demise, and Pete fled.
He returned to Hollow Bastion to see if what he'd heard was true and found the fortress devoid of activity, until Maleficent's pet raven, Diablo appeared, a precursor to her own return. When she finally made her way back, he informed her of the breakdown of her villain's alliance, and the pair set their sights on raising more Heartless and finding a new castle.
Pete was present to help Hades and Scar with their respective attempts to snuf out their enemies, but both plots ended in failure. After being admonished by Maleficent, he began pining for the old days, causing a portal to Timeless River to open up. Going back into the past to steal Disney Castle's treasured Cornerstone of Light, which would enable Maleficent to take it over, Pete found unexpected resistance in the form of the Keyblade Master, and himself from the past. By that point, Past-Pete had not yet turned evil, and they thwarted the scheme. Sora never considered Pete much of a threat due to Pete's incompetence (Sora once describe him as "Not smart enough to tie his own shoes")
During the invasion of Hollow Bastion, Pete fled in the face of the Nobodies.
He and Maleficent turned up one last time in The Castle That Never Was, seeking to take it for their own. When Ansem the Wise's machine to encode Kingdom Hearts exploded, it caused the creation of thousands of Heartless. Knowing the the Keyblade Master and his friends were the only ones who could stop Xemnas, Maleficent volunteered to hold off the Heartless, on the condition that when they'd destroyed them all the Castle would be hers. Pete suggested fleeing, causing Maleficent to dismiss him, but a conversation with Mickey convinced him to stand and fight. Their fate is currently unknown.
Pete's fear of Organization XIII, as opposed of Maleficent's delusory confidence, seems well-founded and his attempts to flee when facing the Nobodies may have been, in a way, the rational decision on his part.
