Dark Link

Dark Link (also known as Shadow Link, Link's Shadow) is an evil version of Link first appearing in The Adventure of Link and is one of the most well-known enemy characters in the The Legend of Zelda universe, mostly due to his likeness and ability matching that of the protagonist, Link. It has been speculated that his popularity is so great in part because he imitates almost every move Link makes, as if Link is fighting himself rather than a separate 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 doppelgänger 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 gray instead of green, Along with his hair being either a shadow black or a dark gray. The majority of the Dark Links are left handed but in some appearances (particularly when there was more than 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 prominent feature against his dark visage.

Soundtracks/Themes
During his many appearances Dark Link has had different soundtracks played to commemorate the moment of his presence. The names of the soundtracks/themes are as follows:

The Adventure of Link: Boss Battle Ocarina of Time: Middle Boss Battle Four Swords Adventures: Shadow Link, Boss Battle Twilight Princess: The Dark Interlopers

The Adventure of Link
In his first appearance in the series Dark Link is known as Link's Shadow (リンクの影, Rinku no Kage) and appears as 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.

Ocarina of Time
Appearing as a mini-boss in Ocarina of Time's Water Temple where he takes over his own reflection as he battles his good counterpart in an oasis of sorts. Dark Link (ダークリンク, Daaku Rinku) 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, the Deku Nuts, 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 Link 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 enough time passes, he will fight on his own, countering every sword attack. Din's Fire is the best option in this part of the battle. If Link performs a sword lunge or the thrust, 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 might have been created by Ganondorf as a mirror reflection of whoever entered the temple, but others believe that the shadow link was sent by the gods Din, Nayru, and Farore to test his abilities. To date, this is Dark Link's only vocal appearance, sharing the same voice as Link's but heavily distorted, giving it a demonic feel.

Oracle of Ages
During the second phase of the final battle, Veran created 4 red-eyed copies of Link that moved opposite of him as obstacles. These Shadow Links did not attack, however, and were useful in recovering health, as each one dropped one heart each. They are also compared to Arm-Mimics and Mask-Mimics.

A Link to the Past/Four Swords
On the Game Boy Advance port, after beating both A Link to the Past and the multiplayer Four Swords game, the Palace of the Four Sword is unlocked. The final boss of this dungeon are four Shadow Links, each with a unique tunic and powers. Their tunics correspond to the colors of the Links that hold the Four Sword: Green, Red, Blue, and Purple. Each Shadow Link has a different power, and the powers of the previous ones. These powers include using Link's charge, sword beam, a jump attack, and the hurricane blade.

Four Swords Adventures
In Four Swords Adventures Dark Link is referred to as Shadow Link (シャドウリンク, Shadou Rinku) 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 produces copies of himself and plagues Hyrule by attacking its citizens, who blame the Links for his misdeeds. Dark Link 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 color, 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.

Twilight Princess
Dark Link makes a cameo appearance during a cut-scene in Twilight Princess that tells the tale of how the Twili race was banished to the Twilight Realm. Portraying the powerful Dark Interlopers who sought to control the Sacred Realm, Dark Link managed to destroy a Link (portraying a common citizen) before he was banished to the Twilight Realm by the Light Spirits.

Super Smash Bros. Melee
Dark Link, as he appears in The Adventure of Link and Ocarina of Time appears in the Event-match "Link's Adventure", where he must be defeated with Link on the Temple stage. As this however is a simple color-swap of Link however, this can be applied to any character through the Debug menu only accessible through Action Replay.

Super Smash Bros. Brawl
Link is able to switch into Dark Link as an alternate costume in Super Smash Bros. Brawl. Also, Melee's Dark Link boss (which in turn is based of Dark Link from The Adventure of Link and Ocarina of Time) reappears in the Event-match "Dark Link Duel" on the Bridge of Eldin stage. However, the Dark Link in this Event is completely black, as opposed to Link's Dark Link alternate costume, which is mostly gray/black with red eyes. As in Melee, Link is the only option to fight against Dark Link. However, unlike Melee, this battle is fought as a Stamina match.

Manga
Within the Ocarina of Time manga, Link meets up with his shadowed doppleganger at Kakariko Village. From Beneath the Well, Dark Link emerges, ready to defeat the original Link. The original Link managed to defeat his dark self by learning that the shadow monster is only as good as Link was then. So to defeat him, Link had to become better than he was before. Slicing Dark Link in half, the dark hero was not yet done. Dark Link then returned riding on a Dark Epona. Link countered and defeated Dark Link once again with the use of his own Epona. This Dark Link replaced Bongo Bongo as boss. Most likely because the Shadow Temple didn't appear in the manga.

Four Swords Plus is the manga for the Four Swords Adventure game. In the manga, Shadow Link is shown as a spawn of the mirror. He first appears when Link pulls the Four Sword from the pedestal, and re-appears numerous times to halt the four Links' progress. At the end, Shadow Link breaks the Dark Mirror, killing Vaati. It should also be noted that Dark Link wasn't evil, but he wanted to be recognized by the other Links.

Man of Mystery
No one knows what Dark Link's origins are, but there are many speculations. 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 The Legend of Zelda, hence Dark Link's appearance in The Adventure of Link).

Some say that Dark Link was created out of Link's heroism: because Link is the hero that he is, Dark Link arose 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. With that in mind, many also believe that Dark Link cannot truly be defeated because this might also result in Link's death. Yet another theory is that, since Link needed to be born immaculate (sinless) 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?

However it seems more likely that Dark Link is simply a spell cast by Ganondorf, or Thunderbird.

Dark Mirror
The Dark Mirror in Four Swords Adventures is said to be the 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.

Tale 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. These Dark Links are merely a representation of evil.

Trivia

 * It has been noted that Dark Link is akin to Link in The Legend of Zelda as Peter Pan's shadow was to Peter Pan in the production, Peter Pan. Both characters struggle with their shadows, both defeating them in order to move on with their quests, and both shadows have similar moves and actions used to try to outwit their true form. The fact that Peter Pan and Link both have similar attire only emphasizes such a connection. Despite these similarities, however, there has been no confirmation of a connection between the two by Nintendo, and any perceived connection is merely fan speculation.