In Kirby & the Amazing Mirror, there are four copies of Kirby. Dark Meta Knight splits the original Kirby into four differently colored versions at the beginning of the adventure.
The four Kirbys are central to the game's cooperative design. Kirby can use the in-game cellphone to summon other Kirbys controlled by additional players or by the computer, allowing the group to explore the Mirror World together. The game was the first Kirby title to support cooperative four-player multiplayer in its main adventure.
The copies are not simply cosmetic duplicates: the group can divide to investigate separate routes, activate mechanisms, and fight enemies across the game's nonlinear map. Shadow Kirby is a separate Mirror World counterpart and is therefore not a fifth playable copy created by Dark Meta Knight. The story ultimately brings the four Kirbys together against Dark Mind and the corrupted Mirror World.