Dark Meta Knight is a darker version of Meta Knight that comes from the Mirror World, thus making him Meta Knight's opposite.
He appears in Kirby & the Amazing Mirror. In the game he slices Kirby into 4 different variations of himself, with Kirby's copies taking red, green and yellow colourization. He then kidnaps Meta Knight and traps him in the Mirror world. They meet again in Radish Ruins where he disguises himself as the real Meta Knight. They fight and beat him then he flees, his disguise begins to fade thus revealing his true form. They eventually meet up with him again in the Mirror world, still disguised as the real Meta Knight, but then the real Meta Knight comes and reveals who the imposter really is and they defeat him once more. He then dies and breaks into pieces like how a Mirror would break.
Dark Meta Knight appears in the game Kirby and the Amazing Mirror 2, debuting in the Candy Constellation area. He first appears under the name of "???" while he is disguised as Meta Knight. He later appears as a boss character, and is revealed to be Dark Meta Knight once the original cuts his costume in two.