Dark Link is one of Ganondorf's creations. He is an evil copy of Link. He first appeared in the Legend of Zelda video game series, and then followed his namesake and nemesis Link into Paper Computer Games. His first appearance in a paper computer game was Zelda Game.
He is slated to appear in the upcoming game, Dark Triforce.
Dark Link in Zelda GameEdit
A new version of Dark Link was created 7 years after the events of Ocarina of time, and unlike the Dark Link in Link's dream 7 years ago, this Dark Link is a more highly advanced copy of Link, so much so that you couldn't tell them apart; Not even if they were standing right next to each other. This is definitly Ganondorf's favorite creation because not only will it cause chaos, but it will also make Link look bad. ("Zelda Game")
In our records, there has also appeared an Umbrian version of Link. Umbrians are a race of shadow-people, although their intentions are unknown. If, when, or how, Umbri-Link (as he's known) will appear is unknown. But it's possible he'll be a version of Dark Link. (Chronicles Addendum)