Dark Link

Dark Link (also known Shadow Link, Link's Shadow or in the Japaneses versions Doppelganger) is one of the most well-known enemy characters in the Zelda universe, mostly due to his likeness and ability matching that of the protagonist, Link. It has been speculated that his popularity is so in part because he imitates almost every move Link makes, as if Link is fighting himself rather than a seperate entity; that is, Link and Dark Link are opposite in intentions, but perfectly matched in ability (as well as action).

Attributes of the Dark Links
As the doppelganger of Link in all of his appearances Dark Link bears resemblance to Link in whichever game they're in and wears the same style clothing as him (tunic and a long, floppy cap) with the exception of his entire outfit being black or dark grey instead of green. The majority of the Dark Links are left handed but in some appearances (particularly when there was more then one) they have been shown to favor either hand. Another notable feature aside from the color scheme of his clothes is Dark Link's red eyes which are usually the only prominant feature against his dark visage.

The Adventure of Link
In his first appearance in the series Dark Link is known as Link's Shadow and appears as the leader of the Cult of Ganon and the final boss in the game, he serves as the final test before Link can obtain the Triforce of Courage and wake Princess Zelda. Dark Link is the most difficult opponent to appear during Link's second quest to save Hyrule. In battle he dodges most of the attacks that Link attempts but is vulnerable when he jumps. This flaw can be taken advantage of by simply standing in a corner and repeatedly swinging Link's sword toward Dark Link. Dark Link will attempt to jump at Link and keep running into the attacks making a rather difficult battle seem, less difficult.

Oracle of Ages
During the second phase of the final battle Veran created 4 red-eyed copies of Link that moved opposite him as obstacles. These Shadow Links did not attack, however.

Ocarina of Time
Appearing as a mini-boss in the Water Temple Dark Link mirrors most of Link's movements and attacks, usually defending himself in the process. He also possesses the ability to disappear and spring up from the floor after being hit. To defeat him, Link must use the Megaton Hammer or the Biggoron Sword, or by using  his sword and while L/Z targeting him do a horizontal slash on the opposite side of his shield, which gives you an instant hit. Stocking up on magic potions and using Din's Fire is another option that makes the fight against Dark Link very easy. However, once he is given enough damage, he will fight on his own, countering every sword attack. Din's Fire is the best option in this part of the battle. Whatever you do do not perform a sword lunge as Dark Link will simply jump up and stand on the blade before attacking. Once Dark Link is defeated Link is able to continue on to a room containing the Longshot. This Dark Link was created by Ganondorf as a mirror reflection of whoever entered the temple.

Four Swords Adventures
In this game Dark Link is refered to as Shadow Link and is featured as both a main character, a recurring boss and respawning enemies. Shadow Link had been brought forth by the stolen Dark Mirror and tricks Link into drawing the Four Sword, releasing the ancient wizard Vaati and splitting Link into four Links. He then plagues Hyrule by attacking its citizens causing the citizens to blame the Links for his misdeeds, he produces copies of himself in order to do this. He shows up twice in each stage, where whoever managed to kill him could receive 100 Force Gems. He is also a boss for the Cave of No Return, Village of the Blue Maiden, Desert Temple and The Dark Cloud stages - Where, during each battle except for the Dark Cloud stage, he would eventually take on a colour, and only the corresponding Link could damage him. Shadow Link and his kin are defeated in The Dark Cloud stage when, while the Links engage them in combat, Zelda undoes the seal on the Dark Mirror and takes it into her possession, dispelling them.

Super Smash Bros. Melee
Dark Link also appears in one of the challenge scenarios in Super Smash Bros. Melee, where you must defeat him with Link.

Ocarina of Time (Manga)
In the manga, Dark Link shows up in the well instead of Bongo Bongo. It is actually just a shadow beast that can take the form of anyone it chooses, creating havoc in Kakariko Village. When Link fights him, Dark Link repeats exactly what he does when finally Link does a backflip, that he just learned from Impa, over Dark Link and defeats him. Then the shadow transform into Link again, but this time on a "Dark Epona". Link easily defeats him and thats the end of the shadow beast. Impa tells Link that she is one of the Sages. There is no Bongo Bongo in the manga.

Man of Mystery
No one knows what Dark Link's origins are, but many speculations are out there. Some say that he is the ghost of a past warrior that is related to Link. Others think that, in a sort of dead-man-switch technique, Dark Link was created by Ganon himself as insurance, should he fall to Link's blade (as he did in Legend of Zelda, hence Dark Link's appearance in Zelda II: The Adventure of Link). Some say, just maybe, Dark Link was created out of Link's heroism. Because Link is the hero that he is, Dark Link arose due to complete Link's dark side. Everyone has a good and bad side to them, (Yin and Yang) thus, it is a widely accepted theory that Dark Link is the force that balances Link, and possibly keeps him alive. Yet another theory is that, since Link needed to be born immaculate (sin-less) in order to touch the Master Sword, the gods extracted his dark side from his soul, leaving only his light; his dark side is Dark Link, whose ultimate wish is to reunite himself to his holy counterpart. Regardless of these theories part of Dark Link's popularity is the sheer mystery behind him. Who is he? Why is he intent on combating Link? If, indeed, the before-mentioned theory is true, then, does Link have a dark side to him alone? Is he capable of doing no wrong?

Dark Mirror
The Dark Mirror in Four Swords adventures is that game's source of all the Shadow Links, it is said that one can look into the mirror and pull out their dark reflection. Ganon obviously did this, and stole the mirror, because all of the Links came from this source.

Ancestor of the Twili?
In Twilight Princess, the Light Spirit Lanayru tells Link a story warning him about the corrupting power of the "Fused Shadows", as well as giving their origins. As part of the visual aid, Link and his childhood friend Ilia represent corruptible humans, while the corrupt sorcerers who would become the Twili are represented by three copies of Link with colorless clothing, black skin, and glowing, red eyes. It is debatable whether these Dark Links are merely a representation of evil or are the real ancestors of the Twili (in which case, Dark Link would be related to the Twili).