This is the timeline where Ganondorf killed Link in his final battle with him, leading to the Imprisoning War described in A Link to the Past's backstory.
Before The Adventure of Link
Long ago the King of Hyrule used the full triforce to ensure a golden age upon Hyrule, however when age started to catch up with the King, the monarch realized his son was an unworthy heir as the the mysterious court Magician had corrupted the boy's ambition and now he selfishly aspired to rule Hyrule at any cost.
Fearing the repercussions of his son or the magician getting their hands on the full Triforce, the King entrusted the Triforce of Courage to a humble sage who would hide the Triforce of Courage in the Great Palace and create monster guardians to ensure only a hero that was truly worthy could obtain the Triforce. Only the King's daughter was told the location of the Triforce of Courage.
The Adventure of Link
When Link destroyed the Thunderbird and reached the end of the Great Palace, he encountered the sage with the Triforce of Courage. The sage was unsure Link was worthy and as a final test waved his staff to bring Link's Shadow to life, filled with all of Link's inner evil.
Link's Shadow was defeated and destroyed by Link, symbolizing the hero overcoming his inner demons. With Link's victory, the sage knew he was the hero he had waited all these years for and entrusted the Triforce of Courage to him.
Manga and Comics
Yuu Mishouzaki Manga
In the manga adaptation of Adventure on Link by Yuu Mishouzaki, Link's Shadow is instead the alternate form of Ganon, the result of his followers sprinkling Link's blood on his ashes. Shadow appears as ashen skinned version of the manga version Link with pointed teeth and a slitted pupils.
In the Valiant comics adaptation, Link's shadow is known simply as Shadow. He is a shapeshifting monster created by Ganon and exactly resembles Link in his regular form. In addition to being able to take the form of Link, Shadow also takes Zelda's form.
In the Maru Ran manga, the existence of Link's Shadow is foreshadowed in a Nightmare Link has about Hyrule under the Magician and Ganon's rule, in the dream, Ganon's top general bears Link's face.
When Link's Shadow's appears in person, he is created from Link's reflection in the mirror by the Sage guarding the Triforce who explains only someone who can conquer the evil inside their heart is worthy of the Triforce.
When the bloodthirsty clone comes into existence, he immediately engages Link in a bloodthirsty battle, keeping the hero on the defensive due to the evil creation's knowledge of Link's mind due to being the evil within him. He psychs Links out by mentioning all his friends that died on his journey for the Triforce and gains the advantage, announcing his intent to use to the Triforce to rule Hyrule.
Link's sentient Parrot friend, Watto, intervenes to save Link, but the Shadow knocks him to the floor. Link's Shadow then stabs the wounded Watto, killing him in cold blood. Enraged Link attacks his double and bisects the evil twin. However Link's Shadow still lives, taunting Link that he can never be defeated, but Link says so long as there is a Hyrule to protect, he can purge his heart of evil thoughts and when he looks in the mirror, he will see only himself.
With Link's resolve, Link's dark doppelganger disintegrates. When Link's Shadow is destroyed by Link, the Triforce's guardian revives Watto and grants Link the Triforce of Courage.
Link's Shadow's appearance in the manga is similar to the hero's but with black clothes, baggy eyes and a unhinged grin.
- Link's Shadow, Dark Link, and Shadow Link were once considered the same entity. However, since the release of the Hyrule Historia, it has been confirmed Link's Shadow is a separate entity from the two others. Though Zelda Universe treats the three as one.
- Although Hyrule Historia calls him Link's Shadow, he is referred as Shadow Link in NES Remix 2 and Dark Link on Zelda.com. His true name can be debatable.
- There is an easy way for Link to defeat Link's Shadow, though as a result of simplifying his AI when Zelda II was ported from the Famicom. If Link stands in the corner and kneels, he can easily stab the Shadow. After this happens, the latter will fall back before approaching Link. This process can be repeated until the boss is defeated.
- Link's Shadow is often mistaken for the primary antagonist of the game when he is just the final boss who hadn't been created until Link met the Triforce keeper at the end of the game.