Villains

The Villains are a group of scoundrels from various worlds who seek to harness the power of the Heartless. They are led by Maleficent, and originally had the goal of capturing the seven Princesses of Heart and taking control of Kingdom Hearts, to rule all worlds. After their first defeat at the hands of Sora, they are much less organized, and while they occasionally cooperate on a one-on-one basis, they no longer work in concert and follow their own goals.

Each Villain is usually the boss battle for their native world.

Kingdom Hearts Birth by Sleep
After discovering the darkness, Maleficent began to gather people for her group, starting with Pete after he was expelled from his world.

Kingdom Hearts
Maleficent, along with the organization members, Hades, Jafar, Ursula, Oogie Boogie, and Captain Hook, kidnap the Princesses of the Heart to their lair at Hollow Bastion, and work to prevent Sora from finding the worlds' Keyholes. They observe Clayton as a possible member, but he is consumed by the darkness. To fulfill his purposes, Maleficent tricks Riku into joining them.

Kingdom Hearts 358/2 Days
While searching for Jafar's Lamp in Agrabah, Pete is followed by Axel and Roxas when they come across the villain in the Marketplace as he was looking for a secret entrance out of town to the Cave of Wonders. Later, Pete encounters Roxas and Xion during another mission in Agrabah in the the Cave of Wonders and engages them in battle.

Later, Pete appears in Neverland, making fake treasure maps for Captain Hook to follow, relying on the pirate's greed to conjure up tons of Heartless in his mad quest for riches.

Kingdom Hearts II
After Maleficent was resurrected, she and Pete try to reunite a new group. Pete contacts a former member, Hades, and try to get Jafar back, in addition to trying to find new members, such as Barbossa or Scar. Maleficent resuscitates Oogie Boogie and collaborates with him, however, he seems to have lost respect for her. After losing their base in Hollow Bastion, Maleficent thinks about turning the Castle That Never Was into her new base.

Kingdom Hearts coded
Maleficent sends Pete to Disney Castle to spy on King Mickey, and when Data-Riku transports Mickey, Donald, Goofy, and Jiminy Cricket into the Datascape, Pete gets pulled in as well, appearing in a hub between the data worlds. He calls Maleficent, who uses her magic to enter as well.

Kingdom Hearts Dream Drop Distance
At Disney Castle, Maleficent reveals to Mickey how Xehanort once told her of other worlds and the seven hearts of pure light that would enable her to rule them. However, due to the complexity of the worlds, Maleficent decides to take a different approach, using the worlds' data. When Mickey refuses to yield, she attempts to attack him with her magic. However, the magical flames are blocked by one of Lea's Chakrams, while the other surprises Pete and allows Minnie to escape.

Trivia

 * The track "Villains of a Sort" is used for most cutscenes involving the Villains.